While parking yesterday I saw a couple of these Honda R&D vehicles for DSRC (Dedicated Short Range Communications) parked next to each other. They initially caught my eye because each has one or more small, round antennas stuck on the top. A quick look around online shows that each manufacturer seems to be doing some manner of DSRC work for things ranging from freight management to toll booths, collision avoidance / proximity notification, traffic detection, etc. This sounds like it could be interesting to play with.
(Yes, this photo was taken in a very public parking garage.)
Here, have a few more moblog photos: