What would be a highly portable, fun instrument to play?
When I say, portable, I mean small enough to fit in a backpack. I play guitar and sometimes it's difficult to travel with. I also play a little piano but, well...that's not coming with me anywhere, is it?
The obvious answer for me would be a ukelele which I'm definitely interested in buying (does anyone know of an affordable type of decent quality?). But I'm also thinking about something more unusual. I recently discovered karimbas--or thumb pianos (http://en.wikipedia.org/wiki/Thumb_piano)--but the cheaper ones seem slightly limited with only one octave.
So, if anyone has any experience or any interesting suggestions, please let me know. I'd probably be best at figuring out something with strings (like a uke) but I'm up for anything.