Last year the Cavaliers clinched the division on March 18th. The prior year, Celtics clinched their division on March 19th.
When are the Bulls clinching? As of this post, they are 14.5 games ahead of the Pacers and the Bulls have played 57 games. That is the equivalent of having played 71.5 games. So basically 10 Bull wins, or 10 Pacer losses or a combination thereof and the Bulls have clinched. I don't know what the earliest clinch date ever is, but I believe the Bulls will be very close to the earliest clinch date and that date will be...
March 12th, 2011 against the Utah Jazz.
Pick your date. Consider this a B&B competition as no prizes to the winner.