Mac: While we're usually fans of keyboard shortcuts for the quickest way to use your computer, sometimes some fancy gestures are just too fun not to use. Gestr is an app that allows you to create and customise your own set of gestures to launch apps.
Gestr is similar to BetterTouchTool and Jitouch, but it's less intimidating to use. Gestr only deals with app launching. Launch Gestr, create a Gestr for your apps, and you can instantly launch it with a simple gesture. You can also add gestures to specific bookmarks, utilities and system preferences. Once you've created a few gestures, just tap your trackpad, draw the gesture and the app's launched right away.
It's certainly not as feature-packed as something like BetterTouchTool, but that's part of the appeal. It's really easy to set up use right away.