Windows/Mac/Linux (AIR): It's always fun to throw a party and let your guests get goofy with a camera. Free photo app Party Booth creates photo-booth-style picture strips from a webcam, and can automatically upload them to Facebook, Twitter or other services.
After setting up your camera and connecting Party Booth to whatever social/photo service you'd like — and, most definitely, making sure you know just how visible those photos might be — it's a very simple app to use, which might be perfect for, well, later in the night. Simply hit the space bar, and a timer ticks off until Party Booth captures four frames of your guests. You can set up the photos for old-time, vertical four-strips, two-by-two grids, any many other options, including the addition of custom backgrounds.
Don't like the idea of automatic uploads? Set Party Booth to just save to your disk, and your job is safe on Monday.
It must be said that Party Booth costs $US38 for a full version, which isn't cheap for software you'll probably only use every so often. It does, however, offer a 10-day free trial that only nags you upon launching the app. That's perfect for giving it a go at an upcoming shindig, and it makes a nice complement to other photo projects to document your party.
Party Booth runs on Windows, Mac and Linux under Adobe AIR.