Open Automator
- Choose Service
- - Change method of input to no input
- - - From the Finder section, drag in Launch Application
- - - - Change the application to iCal
- - - - - Save this workflow and name it something, Open iCal for example
Open System Preferences
- Keyboard section; Keyboard Shortcuts tab
- - Click Services on the left
- - - Scroll down to General until you see your new service
- - - - Make sure it is checked and then double click far to the right of it
- - - - - Now press your desired keyboard shortcut
Now every time you press this shortcut, iCal will pop up. If iCal wasnt running when you pressed the shortcut, then it will launch and then become the foremost application.