There's nothing unique about players having shooting contests at the end of a day's practice. The Wizards put on a famous one two seasons ago, and this type of thing goes on all the time. But as far as competitive fire goes, I think you'll be hard pressed to find anyone who would take it to the level that Sasha Vujacic did after yesterday's practice.
As he was leaving the court, Sasha threw up a 50-foot hook shot, and said "take that, Kob!" as he walked towards the door. The shot clanked off the rim, but Kobe issued a challenge: "I'll give you 20 bucks if you make that." That was all Sasha needed to hear. He spent (by most estimates) the next 20 minutes launching these hook shots, with Kobe in his ear the entire time. Thankfully, Mirjam Swanson of the Press Enterprise was filming, and put together some highlights.
I encourage you to read the entire account of how this played out, it's really pretty hilarious. For a lousy $20, Sasha absolutely wouldn't quit until he hit one of these shots. Now we know why they call him The Machine.