Prior to the Celtics visiting the White House, it was announced that Darius Miles would be suspended for the first 10 games of the '08-'09 season. The suspension was handed down to Miles allegedly taking phentarmine. Miles, however, still doesn't know how he tested positive. From SLAM Online:

Darius Miles, the newest member of the defending champion Boston Celtics, isn’t allowed to suit up for the first 10 games of the 2008-’09 season. This is because the League found him guilty of having taken phentarmine (most commonly found in diet pills), a baned stimulant.

For Miles, this is all very confusing, since he claims to never having swallowed any diet pills. From ESPN:

“I wish I knew. I really do wish I knew, but [Celtics president] Danny Ainge told me ‘leave it alone,’ so I left it alone,” Miles said

And this from the Boston Herald, in which Miles complains about the timing of the announcement of his suspension:

“So they announce it on the day that the Celtics go to the White House (to be honored as last season’s champions). What is it that everyone heard that day? The Celtics go to the White House and Darius Miles gets suspended for 10 games. That was messed up.”