The eject key sits in the upper right corner of most modern Apple keyboards. On my big iMac with its SuperDrive, it occasionally gets pressed when I need to kick out a backup DVD, but the rest of the time it sits alone. It's even worse on a MacBook Air. With no SuperDrive to speak of, the eject key was replaced with a tiny power button and the eject function moved to the F12 key next door. What do you do with a key that has outlived its usefulness? Give it another reason to live!
This all got started when one of the employees at Other World Computing, the folks who make all of those fast internal SSDs for MacBook Pros and other devices, had the optical drive on his 2011 MacBook Pro removed and replaced with an OWC Data Doubler + 750 GB hard disk drive. OWC's Erik was already enjoying a speedy 480 GB SSD as his startup drive in the MacBook Pro, but wanted the luxury of more storage.
With his eject key now taking up space and not paying the rent, Erik looked around and found a free app called KeyRemap4MacBook. The app remaps most of the non-alphanumeric keys on the Macbook keyboard to a set of different functions. Not only can you assign duplicate keys (Option and Command keys, for example) to perform different functions, but KeyRemap4MacBook makes keys do different things depending on what app you're currently using (note that you can already do this to a point using Keyboard Shortcuts in System Preferences).
Erik used the app to remap his eject key to be a forward delete key (Fn + Delete), and noted that if he does happen to have an external optical drive connected to the MBP, KeyRemap4MacBook thoughtfully provides a way to use the eject key as, well, an eject key.
One thing that KeyRemap4MacBook doesn't do is use a standard delay when pressed, so there's a companion app called NoEjectDelay by the same developer that clears the eject key delay.
The inquiring minds at TUAW want to know what function you'd remap your eject key to perform, or if you'd just turn the eject key into one-half of a pair of cufflinks. Leave us a note in the comments below.