Tangram for Breakfast

True, you can use software to play Tangram, but it's not as satisfying as the real life hands-on version.

Amazon sells a splendid wooden version for £2.69:

It's the perfect way of (gently) waking your brain up in the morning -- coffee is good, but a Tangram puzzle + coffee is superior.  Also works great if you're stuck on a coding problem -- solve the tangram, and the solution to the other thingy just pops up in your mind a lot of the time.

Try some cats, or a paradox.