I put together a presentation that didn't get time at the first AnnArbor.rb meeting. The topic is "Ruby & Hardware" and is a quick rundown of some cool devices that can run (or be interfaced by) Ruby, such as NabazTag, SqueezeBox, Nokia 770. They're all at various levels of support and functionality, but you can run Ruby on all of them.
Check out the presentation here: Ruby & Hardware.
I'll be talking about them at the November AnnArbor.rb/RubyMI meeting if you want to come by.