What's Your Favorite Gadget to Aimlessly Fool Around With?

I just picked up a cheapo infrared thermometer, a laser-aimed sensor that tells you the surface temperature of whatever you point it at. I didn't really need one. But now I can't put it down. I've been playing with it for days. And I'm sure there's a gadget you find equally, aimlessly amusing.

I mean it, I've been taking the temperature of just about everything. Boiling water (it's hot!). Ice cubes (they're cold!). I've been temping food fresh out of the microwave, then re-temping it after I blow on it for a second (it gets a little cooler!). My hands, I've discovered, run slightly warmer than my feet. The battery on my laptop is about seven degrees warmer than the touchpad, while the screen splits the difference. Room temperature toilet water is, well, pretty much room temperature (69.8 degrees Fahrenheit!).

Is any of this data useful? Hell no. And I'm probably starting to worry my roommate. (3AM today: "Dude! The TV remote is two degrees cooler than it was when I got home from work!") But my new toy has the perfect mix of attributes that make it infinitely play-with-able: using it only takes a few seconds, and essentially zero thought, and every trigger pull spits out a tiny piece of information. It's intoxicating.

I know you've got some kind of doodad of distraction on your desk, in your junk drawer, or on a shelf somewhere. The kind of thing you can pick up and just fidget with for hours and hours, accomplishing nothing but pleasant idleness. What's yours?