My co-worker was a big prankster until he took it too far a few times and had to back way off. We still do harmless pranks, but nothing to the extent that we/he used to. One of my favorites out of sheer simplicity is seeing an unlocked and unmanned computer, changing the background picture, then completely covering it with any programs still open. Our most recent male hire came back to this as his new desktop:
Are there any pranks you guys pull that could get a laugh and be acceptable in the workplace?