The On/Off Mug is a simple morning early-warning system. If your office mates see you coming and the mug is black (Off) they know to keep moving. If they see the white “On” coming at them, they know it’s safe to speak to you without being maimed in your pre-caffeinated state. You aren’t REALLY responsible for anything that happens before that first cup, right? The design uses heat-sensitive pigment, and is dishwasher safe. Your co-workers will thank you. Then again, maybe YOU aren’t the snarling, coffee-deprived monster first thing in the A.M. and you should get a few of these as a gift/hint for those who ARE.

Buy for $25