See also: Interesting BOB Trailer Uses Part 2.
One of my favorite things about BOB Trailers is the proclivity of their use as the base for the odd if not bizarre modification.
Solar Power: Use your BOB to support a large solar array and run electrical appliances wherever you go. Or use it to power the electric hub on your bike.
Electro Power: This BOB has been modified for use as an electric power assist for your bicycle. There is still plenty of room for extra gear.