Back in 2006, about a week or two before my 30th birthday party, I threw together a huge playlist. Perhaps I got a bit overzealous with it, but I saved the playlist and still listen to it from time to time. For curiosity's sake I set it up to play the playlist from start to finish on Saturday night at about 11 pm Central... It's now Monday at about 7:23 pm Central and only about 60% of the list has played. At this rate it probably won't play through until Wednesday night or possibly even Thursday.
Either way, maybe my expectations for the length of my birthday party were a bit unrealistic... but I guarantee there were NO songs repeated that night.
If you're interested in seeing what material was/is on the playlist (although I'm not sure why you would be)... You can find it scrobbling here.