If you do, make sure the players call out, and explain the significance of their moves. If possible, use bigger pieces to show action in areas of the board. Justsilently pushing pieces around may be dramatic to the person across the table from you, but the viewers cant see everything.
I would enjoy watching games of munchkin if your players are witty and dramatic. Mage knight could be fun, if a bit long. Anything could work if you remember the format, and its limitations.
Thanks for the reply! I can promise you that my gaming group doesn't shy away from being vocal and having a good time. I'd love to share the fun we have with others. I'll certainly keep your suggestions in mind if I ever go through with it.