boomloop.com is a social event calendar. with boomloop, you can stay informed about events that might interest you, and can easily connect up with your friends when you want to go out somewhere.

the boomloop API is a REST based API. It can be used to publish and fetch events on boomlop.

read the introduction here: http://code.google.com/p/boomloopapi/wiki/BoomloopAPI, or go straight to the DetailedAPIDescription.