I'd love to see Ben Heck mess around with the On Board Diagnostics port of a car. I like the idea of gathering automobile system data and potentially use it to diagnose issues (that's what the connection is typically used for, I think). I'd love to be able to send info like that to my phone in real time via bluetooth while I'm driving, and there are already products that do that, but they're pretty expensive for what I'd think would be a relatively simple device. The signals aren't standardized among car manufacturers and it'd be interesting to see how Ben and the team tackles an issue like that.
I did a super quick google search and found this page:
http://www.obdii.com/connector.html
Depending on how much the team already knows about OBD systems in autos, it may be useful at least in gauging the scope of a project involving OBD. Keep up the awesome work!