Tib's Eve is interesting.
Where I grew up we have that except it falls on the Wed before Thanksgiving. Everybody under 40 (and some over) goes out Wed night and gets absolutely shitfaced with all of their old friends. It's the only time you ever see most of them after graduating HS. But that night everyone might as well be 18 again, complete with ending up at someone's house until 6 am raiding the parent's liquor cabinet.
It's not the tryptophan that makes people pass out. They're all just hungover as balls.