WowWee's RoboRemote is an aftermarket IR remote control for the company's full range of current and future robots. Intended to make programming the robots more straightforward, it connects via USB to a computer and, with the included software, lets you script macros and routines that are then blasted across via infra-red. All well and good, but not quite enough for the guys over at RoboCommunity; they've been exploring ways to add new sensors and inputs to the WowWee stable courtesy of a hacked RoboRemote.
The basic idea is to open up the casing, solder in some new terminals that trigger what would normally be button presses, and have scripted macros play when that happens. RoboCommunity do a good job of making it all look pretty straightforward, and given that the remote itself only costs $19 even if you do muck things up you won't be too out of pocket replacing it.
What's really clever about this is that it means you can hack your Robosapien (or whatever else from WowWee) without needing to physically modify it. RoboCommunity call that "opto-isolation" - where the two electrical systems are separated - but us laymen call it "being sensible when you're hacking an expensive robot". It also lets you control multiple robots from one remote. Some suggestions for sensors include those that react to light or magnetic fields, noise or moisture, or augmenting the robot's original obstacle-avoidance skills.