A new (to me) Kent Traveller folding bike. A co-worker gave it to me when the derailleur rusted shut and snapped in half...rather than just purchasing a new derailleur he decided to purchase an entirely new bike.
Not that fond of derailleurs myself in this coastal salt air, I broke and shortened the chain, placed it on the third of five gears and made a nimble one-speed hill-climber out of it! Top speed no more than about 12MPH or so, but I can maintain that speed up moderate hills and slopes and stay fresh as a daisy doing it...
I do have a Sturmey-Archer internal 3-speed hub and shifter lying about-i'll probably build a nice 20" wheel around it later this month and see which configuration I prefer.