You know that sudden motion sensor that's buried in your Mac to protect your hard drive? Want to have a little fun with it? Then check out Liquid Mac, a neat little app that makes your laptop's screen look like it's filled with colored water.
Once you've downloaded the app, select the color and response sensitivity you want, then gently tilt your laptop and watch the fluid splash around the screen. It's oddly soothing, actually, unless you slosh it around too fast and make yourself nauseous.
When you tire of making waves, adjust the settings to represent beads and watch it rain on your screen. To see Liquid Mac in action, check out this cool video.