Well, I don't know the technicalities of wedding crashing; but I was not on the guest list, and I just walked in; and I knew the Bride and Groom distantly through acquaintances. So. I think that qualifies.
I was helping 2 friends get ready for the celebration; Doing their hair, and picking outfits; when my friend suggested I just come to the reception party. She insisted it would be a small enough crowd and nobody would care. Plus there was an open bar! Naturally, I resisted at first, wanting to be respectful of such an event; but once I heard "open bar" I was in!
It went down quite fabulously. I strolled in about an hour into the reception; and joined my party girls in the back corner. We commandeered a few bottles of wine and danced our bootys off.
The open bar turned out to be a very bad idea. The ladies started dropping like flies by 10pm. at about 10:15 I joined that fail train and snuck out the door to head home; only to be followed by a night of Porcelain throne worship.
Over all, I'd say it was a success.