Kobe! LeBron! Melo! Dwight! Trevor! (Trevor?)

In a pair of conference finals that have been as electric as any in decades, the signature moments have come not only from superstars but also from unlikely figures such as the Lakers' Trevor Ariza, who, with the game on the line, has been stealing something more important than the spotlight

When Lakers forward Trevor Ariza is facing a steep deficit late in a game of around-the-world, he turns to a strategy that inevitably rattles opponents and sparks comebacks. He calls timeout, walks casually to the spot on the court where players have left their personal items, and steals his adversary's car keys.

Since NBA players do not generally stash the keys to their Escalades on the bench, Ariza has resorted to a different kind of larceny in the Western Conference finals. Twice in the first three games, with the Lakers leading the Nuggets by two points and less than 40 seconds remaining, Ariza dashed across the court to swipe a lollipop of an inbounds pass and cinch a Los Angeles victory. "I'm like Ed Reed," Ariza says, channeling the Baltimore Ravens' Pro Bowl safety also noted for his game-changing plays and closing speed.

In a pair of spellbinding conference finals unrivaled for twists and turns, Ariza is a 6'8" emblem of the laws of basketball improbability. Not long ago he was jettisoned by a lottery team and wasn't trusted to take a jump shot; his NBA future, if he had one, looked as if it would be measured in 10-day contracts. To see Ariza now, finishing L.A.'s fast break, sinking a succession of fourth-quarter threes and defending the opposing team's best player so that Kobe Bryant can preserve his invaluable energy, is among the postseason's most surprising sights. Ariza is a reminder that titles are not won by brand names alone.

Call the first week of the conference finals May Madness—except the losers were getting a chance to exact revenge. Of the first five games (three between the Nuggets and the Lakers, two between the Cavaliers and the Magic) none was decided by more than six points, none was resolved until the last minute, and all featured severe momentum swings, impromptu tactical adjustments and heart-in-throat finishes. There was Kobe switching assignments to cover Carmelo Anthony, and Anthony switching to take Bryant. There was Orlando wiping out a 16-point deficit to win Game 1 in Cleveland, then rallying from 23 down two nights later. But then there was LeBron James, catching an inbounds pass with one second left in Game 2 and draining a 24-foot fadeaway from the top of the key that resuscitated his city's quest for its first major sports championship in 45 years.

How did the league's MVP assess the most dramatic shot of his career? "For me," James deadpanned, "a second is a lot of time."

James's dagger was Michael Jordan over Craig Ehlo, only deeper and a whole lot sweeter for the hard-luck crowd at Quicken Loans Arena. The most poignant reaction belonged to point guard Mo Williams, who had thrown the inbounds pass but then was physically incapable of celebrating the shot. Crumpling to the floor, Williams held his face in his hands, a la Duke's Thomas Hill after the buzzer beater by Christian Laettner against Kentucky in the 1992 East Regional final. But then the Magic, unbowed, came back to win Game 3 in Orlando 99--89, getting another strong night from Ariza's Eastern Conference counterpart, 6'6" reserve Mickael Pietrus, who has also impressed with his deep shooting and hectoring D. The NBA's final four is matching the college version thrill for thrill, heartbreak for heartbreak.

Corporate sponsors from Nike to Vitamin Water have banked entire advertising campaigns on the Kobe-LeBron battle royal that was seemingly scheduled for the first week of June. But as Nuggets guard Jason Hart put it, "Basketball cannot be planned." After both the Lakers and the Cavs had lost a home game, it was suggested to Anthony that he might want to start filming his own commercial with Orlando's Dwight Howard in anticipation of the Finals. "That," he said with a party crasher's devious grin, "would make a lot of people really mad."

No team is having more fun on this stage than the Nuggets, with their Mohawks, dreadlocks and Technicolor tattoos. They have the only player in the NBA who has come back from two micro-fracture surgeries (Kenyon Martin) and the only current player who has served a two-year ban for drug use (Chris Andersen). Their center is a cancer survivor (Nené), as is their head coach (George Karl). Their best perimeter defender (Dahntay Jones) was playing a year ago for the Fort Wayne Mad Ants of the Development League. "This is the team you'd want to have a beer with," says Nuggets general manager Mark Warkentien.

These Nuggets are also capable of masterpieces and meltdowns, sometimes on the same day. They outplayed the Lakers in Game 1, beat them in Game 2 on the road and led for most of 3½ quarters in Game 3 in Denver, but they trailed 2--1 in the series because they could not make a simple inbounds pass without Ariza stealing it. As Karl reflected on his pack of "stray dogs"—Warkentien's pet name for the Nuggets—at the beginning of the series, he was reminded of the cast of characters from his favorite Jack Nicholson movie, One Flew Over The Cuckoo's Nest. "Sometimes," Karl acknowledged, "I feel like I'm Jack."

Though the Lakers may have the most talent in the league, their hunger often comes into question. They can appear as if they expect loose balls to simply bounce into their hands. They feed the laid-back Los Angeles stereotype—with the exception of the one starter who is actually from L.A., Ariza, 23, who grew up in Inglewood. (When Bryant was a rookie playing at the Forum, Ariza went to the parking lot one day to get his autograph.) After one season at UCLA, he was drafted 43rd by the Knicks in 2004 and then took a bumpy road back home. Ariza was called delusional by New York coach Larry Brown for expecting meaningful minutes and in February 2006 was shipped to Orlando, which then shipped him to L.A. in November 2007. With a style that leans toward scruffy beards and military jackets, he has shown himself to be the sort of scrapper appreciated by the die-hard Lakers fan who remembers that Showtime meant more than Magic and Kareem. "I'm from Watts, and my favorite player was Michael Cooper," says Ariza's trainer, Tony Bland. "Trevor is the new Coop—just 10 shades lighter with lower socks."

"All good teams have a Trevor Ariza," Lakers point guard Derek Fisher says. "He plays with a toughness and aggressiveness that works for us because some guys don't have it." Ariza cannot explain why his motor runs so much faster than some of his teammates', but he credits L.A.'s hypercompetitive pickup basketball scene, which forced him to defend the likes of Baron Davis and Paul Pierce when he was still in high school. DeWitt Cotton, an assistant at Westchester High, where Ariza played alongside five other Division I prospects, says, "He is a true product of L.A. basketball."

The game that defines Ariza's life, though, was held in another hemisphere. His stepfather, Kenny McClary, was a standout at Florida and played professionally in Venezuela. In March 1996, Ariza flew with his mother, Lolita, and younger brothers, Kenny and Tajh, to Caracas to see a game. They stayed in a high-rise hotel, and Trevor taught Tajh how to swim. They were close even for brothers; at home, they slept in the same bed. The day of the game, Trevor went with his mom to the arena. Kenny stayed back at the hotel with Tajh. Just before tip-off Trevor noticed that his stepdad was being pulled from the court. He remembers being ushered into a hallway, then taken to a motorcycle and whisked back to the hotel.

He could hear the sirens before he arrived. Kenny and Tajh had been playing on the balcony of their hotel room when Tajh accidentally fell more than 30 stories to his death. "That was Trevor's heart," Cotton said. "For a long time, he wouldn't talk about it. He'd go into a shell. But Tajh became his drive. He had to make it for his little brother." After Ariza was traded to Orlando, and Cotton moved there to help him acclimate, they laughed and smiled one night as they watched a home video that included Tajh and Trevor play-wrestling. Cotton also noticed one day that the code on Ariza's alarm system spelled Tajh. Ariza even started talking about wanting to have a son. Today, he does have a one-year-old boy, Tajh, who clings to his leg just the way his brother did. "It seems like he's been here before," Ariza says.

Ariza still has a hard time falling asleep when he thinks about his baby brother at night, but on the court he has found peace in his hometown. He has developed from a one-dimensional slasher who was not allowed to shoot outside of 10 feet a few seasons ago into a bona fide deep threat who has made more clutch threes in the playoffs than any Laker besides Bryant. The remaking of Ariza began in January 2008, when he broke his right foot. It might have been the break that saved his career. Ariza always had a sound shooting stroke, but he tended to kick his legs and twist his body in the air. With his foot immobilized, he could neither kick nor twist. "He couldn't even jump," says assistant coach Brian Shaw. "It made him concentrate on his wrist and his arm and not how high he'd get." Last season, Ariza was 5 of 18 from beyond the arc; this season, 61 of 191.

If the conference finals ever hold form, and the Lakers do meet the Cavs as corporate America has ordained, Ariza will likely be assigned to guard James—again. In 2003, when Westchester played St. Vincent--St. Mary of Akron in a nationally televised game, James scored 52 points, including 18 straight during one stretch. For Ariza, what better way to measure how far he has come?

This year's final four will be remembered for LeBron's improbable shot, Kobe's indomitable will and Melo's postseason emergence. But moving forward, someone will have to assume the crucial role that James Posey filled for the Celtics, Bruce Brown for the Spurs and Cooper for the Showtime Lakers. Once again, Ariza may hold the keys.

The NBA's final four is matching the college version thrill for thrill, heartache for heartache.

"Trevor is the new Coop," says Bland. "Just 10 shades lighter and with lower socks."

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Photograph by JOHN W. MCDONOUGH

LANE ATTRACTION The hard-driving Bryant averaged nearly 38 points in the Lakers' first three games against the Nuggets.

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BOB ROSATO (JAMES)

BATTLE READY Ariza was eager to defend Anthony, who had Denver's hottest hand.

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Photograph by JOHN W. MCDONOUGH

POWER PLAY Howard was denied by James in Game 1. but his 24 points in Game 3 helped the Magic take a 2-1 series lead.

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Photograph by JOHN W. MCDONOUGH

BACK-UP PLAN The driven Ariza will use any means (including Pau Gasol) to get to the rim.