Does random memory cheat on you?
How many HTML elements (according to the HTML 4 specification) can you name in 5 minutes? ( 91 elements total )
How many CSS properties (Level 2) can you name in 7 minutes? ( 122 properties total )
These are two interesting puzzles for a while that allow you to check your memory. After passing the test, you can get a nice button with the results. Pampering of course, but interesting.
Do not peek into the tooltip;)