Print the CLA, sign it and scan it (or use a camera to photograph it) and e-mail it to hello(at)robovm.com. Include your GitHub user name in the e-mail.
A bit wacky indeed. For what it's worth when dealing with this stuff I use Apple's Preview App's signature feature. It's pretty neat. You take a photo of your signature with your webcam and place/resize it as necessary. I create a new signature each time (paranoia) but if you have to do this a lot you can have Preview save it for later.
