Beertris
One particular place we like to hang out at is Barcade in Brooklyn. It's a converted garage-to-bar, with an excellent selection of micro brews and walls lined with 80's arcade games. If you happen to be in the New York area, and enjoy such things, it is definitely worth checking out.
Outside the venue there's a wall covered in wooden tiles, each tile having attached to it 10x10 bottle caps, and patrons are allowed to contribute their own creations if they want. There's a Space Invaders guy, a Canadian Flag, and much more. Here's what we gave them:
Yes, Beertris.