Acererak:
Stick a battery on it, have it communicate with an Uno with a motor controller and you got yourself an RC car. Good job.
Yes, the next step in this project would be a LiPo batter backpack. Nothing baked into the Esplora so I'll have to roll one myself.
I'm thinking the Adafruit LiPo unit USB LiIon/LiPoly charger [v1.2] : ID 259 : Adafruit Industries, Unique & fun DIY electronics and kits or USB/DC Lithium Polymer battery charger 5-12V [3.7/4.2v cells] : ID 280 : Adafruit Industries, Unique & fun DIY electronics and kits but they probably will not output 5 volts.
Also, which connection to use to output the juice - I was thinking of hijacking one of the TinkerKit connectors to push in 5 volts.
Anyone have good thoughts?