There's a huge party in Leiden every year on and around October 3. If you're interested in the historical context, check out the wiki entry. If you're interested in the party, just pop by on the evening of the 2nd or 3rd - and be prepared for chaos.

A great portion of the center of Leiden is transformed into a funfair, with lots of music and beer. Thousands of people tromp through the streets - most have been drinking for at least 12 hours - and play bumper cars, dance, and try to win stuffed teddy bears.

It doesn't cost anything to check out the spectacle, so hop on the train this weekend and see what the party is all about. But be sure to visit Leiden on a normal weekend, too - the citizens of this quaint town are usually much more subdued.