http://www.newscientisttech.com/article/dn10056-robotic-kayaks-test-underwater-technology.html

I was readng this because my housemate wrote it, but I thought it was really cool, though I'm not sure it is particularly useful.

It would be quite freaky being out sailing and seeing a roboic kayak coming towards me.

So... what crazy invention would you come up with (along these lines)