What could be a better gadget for summer than a foldable bike? Throw it in the back of the car for weekend jaunts or take in on a plane for your summer vacation. Bike Friday makes a variety of foldable bikes including even tandem and triple-seaters which can also be converted back to single bikes. The bikes can be folded quickly or disassembled to fit into a special suitcase that can also become a bicycle trailer. Prices range from $1,495 to $3,450 and there are models for women available. The Bike Friday team will also make special custom bicycles for those with special requirements.