What Do You Do To Celebrate a Big Accomplishment?

Just this evening, I finished a big project at work that I've been working on by myself for almost a year. It's not perfect and there are lots of places where I would want to improve / extend it, but it works! I'm really happy that I've been able to get it up and running.

What should I do to celebrate? Do you have any traditions / rituals you or your team do when you finish a project?