Some people call it 'Pollyanna', 'Yankee Swap', 'Thieving Secret Santa', or 'Parcel Pass', but the peeps at my work call it a 'White Elephant' gift exchange. We were instructed to bring an item from home we really did not want (a "what the heck am I gonna do with this?" kind of thing), wrap it, and bring it in. Once the first one is opened, anyone else can either pick from the pile or steal an already-opened present.
There were 20 presents on the table of our big conference room and this is a shot of reactions once unwrapping of one of the funniest items there occurred. One of my coworkers (not pictured) framed an x-ray of her mouth from when she had her wisdom teeth removed, and she captioned: "From My Mouth To Your House - Merry Christmas!"