When people at the entrance were checking, did they just let you in or did you sneak in somehow?
Actually crashing parties is good fun. I made a Facebook app that lists all events friends of yours with the same current location have been invited to (that the privacy settings allow), which often ends up with house parties on the list. Naturally, I like to check out some of these house parties.
https://apps.facebook.com/sortonsevents/
Forgive any bugs; I've had a JSON dump saved for a few weeks now for troubleshooting. It generally works for me and developing it further doesn't seem to have many benefits. It's built with Google Web Toolkit.