CLCL Lite is a universal launcher.
By double/triple pressing a modifier key (Command/Option), you can launch/activate application. You can also open URL in web browser, and switch last active application.
1. Launch CLCL Lite
2. Click CLCL Lite's icon in menu bar
3. Choose "Preferences..." from menu
4. Choose a modifier key you want to register from "Hot Key"
5. Choose an action you want to assign to hot key from "Action"
6. Activate an action to double/triple press a modifier key