I work part time, only 2 days a week. I'm always in for a surprise when I come in to my desk. Either a stack of computers to work on (4 yesterday), a new server just sitting there (not even burning in, just there). Network cables disappear, PS/2 to AT adapter disappears off the back of my computer (I have a switch box and need the adapter to use my keyboard). I've had 4 desk chairs taken from me in the past month. Come in Monday, got donuts from the previous Wednesday, or a cupcake, or whatever.
All the crap gets pretty annoying. Takes me 20 minutes when I get there each day to track down missing stuff and clean up the mess. I always leave the cube nice and neat (get in trouble if I don't), and my boss says something to me everytime I go in, telling me I need to keep my area cleaner. I don't even bother explaining.