The blog post introducing the redesigned user pages triggered me looking at my user page at Stack Apps and much to my surprise I'm listed amongst the top 14% this week with 280 reputation, despite no activity of mine but plenty of others. Looking closer at the respective league table for Feb 27, 2011 - Mar 2, 2011 shows other completely unreasonable entries, e.g.:
George Edison is certainly capable of amassing quite some reputation in a short time frame, but the listed 1,912 reputation in just 4 days seem a tiny bit too much ;)
Likewise Sky Sanders used to gain lots of reputation in a short time frame as well, but (unfortunately) hasn't even been active since February 1, so the listed 1,735 reputation are definitely off as well.
The reputation tab targeted for all three profile links above does show the correct (i.e. much lower) reputation gained in recent days.
For reference here is the 'complete' picture ;)
The one thing that obviously springs to mind is the [system-wide recalc of reputation scores] that happened around February 27 indeed; could it be that this 'touches' dates of affected posts/votes eventually?