At the end of his life, George Harrison drove around with a trunk full of ukuleles. Tom Petty told a story about George showing up at his place in the San Fernando Valley (on the other side of the Hollywood Hills), the two of them playing ukes for hours. George left Tom with a uke.
A cool related instrument is the mandolin, an instrument with eight strings (4 X 2), not unlike a 12-string guitar (6 X 2). Commonly used in Country and Bluegrass music. Sam Bush is a master on mandolin, Jerry Garcia's buddy David Grisman pretty good (for a hippie ;-) .