Playing Your Game From A Text Editor
When you're working in your text editor, it can be a nuisance to have to manually switch back to Unity to test your game. This AppleScript will automatically bring Unity to the front and press Command-P to start the game:
<boo>tell application "System Events" tell application "Unity" to activate keystroke "p" using command down end tell</boo>
Enter this into the AppleScript editor, save it in whatever mode your text editor supports (probably 'script'), and place it in a location where your text editor will be able to find it.
For example, with BBEdit, save the script in ~/Library/Application Support/BBEdit/Scripts/. Once you've done that, you can assign a keystroke to launch it using the Scripts Palette. This also works for the free TextWrangler editor, providing you substitute 'TextWrangler' for 'BBEdit' in the above path.