It doesn't sound as good as one made of Hawaiian Koa wood, but this ukulele made entirely out of Lego bricks works exactly like a regular one and it sounds quite nice. In the words of its creator, Ross Crawford:
Realizing I've never owned a uke, I decided I'd try to make one. But instead of using wood, like any normal person, I decided to use LEGO bricks. Of course, there were some challenges: 1) Shape, 2) Strength, 3) Tuning, 4) Intonation.
The model also had to sustain the tension of the strings, which are tuned to C, F, A and D. Quite a feat. [Brothers Brick]