CalmDown is designed to help you deal with the stress generated by your computer every day. CalmDown is a very simple application to help you focus and relax.
When you feel stressed, click the yin-yang added to your menubar in the top right and and choose "calm down."
Your desktop will slowly fade out and be replaced with colors fading in and out. You can use this to help focus your breathing and calm yourself.
NOTE: CalmDown can only be purchased via the Mac App Store (the buy link redirects you to its App Store page). To purchase/download applications via the App Store an Apple account is required.