Check out stats here:
http://www.livejournal.com/community/lj_nifty/87082.html
Stats like that are so easy to do when you're logging to a database. Note to anybody thinking about doing logging to MySQL: no indexes, and INSERT DELAYED. Then you're golden. Maybe one index (time), but what I prefer to do is make a new table every hour, then I can summarize/compress/discard old hours easily.