What I didn't know (it's true: I don't know everything--some would say anything) is that this same tip works with desktop icons.

Specifically, if you're a Windows 7 user, you can increase or decrease the size of your desktop icons just by holding down the Ctrl key and scrolling up or down with the wheel. (Scrolling up makes them larger; down makes them smaller. Natch.)

That's about a zillion times easier than wading into the Control Panel in search of an icon-size setting.

Alas, I can't take credit for this tip; a reader submitted it to Lifehacker. But I can remind you of my all-time favorite mouse-wheel tweak: WizMouse, the free utility that makes the wheel work wherever you point your cursor--no clicking required. It's a must-have.