Why is it that I find the most amazing time-wasters when I have, without a doubt, the least amount of free time ever?
Jig Zone is, yes, jigsaw puzzles on your screen. You can select the puzzle of your choice, even select how many pieces it has. I'm a WHIZ at the six piece option, but you can have up to hundreds of pieces, and a variety of different shapes from classic to bulbs to polygons to... birds. Yes, birds.
Choose your puzzle, choose your cut, and then get to work moving pieces around. You receive a very satisfying "click" sound when pieces fit together. The timer is running, so you are either good at puzzles and will receive some ego stroking as you beat the average person, or if you're like me and suck at them you'll wonder how you can be so bad at certain things despite having a damn good IQ.
Here's a link to the daily puzzle.