Probably the most fun game ever (and educational too!): Crayon Physics
Two caveats with this one, however: it has to be downloaded (something probably not available at work for most people) and requires the devil’s computer (a PC). If either of these things are unavailable to you, please read on.
If you’re not allowed to download at work, don’t fret: an almost-identical game, Magic Pen, is just as sick/awesome, and you can play it online.
You Have to Burn the Rope
Finally, there’s the tightly-named You Have to Burn the Rope. This one is dope. If you don’t believe me, this guy claims that it’s the greatest online game ever. So just play it; it’s Tuesday, you have nothing better to do, and it will take like 5 minutes out of your day. Also, if you are in any way able to turn on the music, it kind of makes the game about 10 times better.
UPDATE: If your skills are too hot for the above games, try your hand at “The World’s Hardest Game.”