Music Composers Unite!
In the vein of impractically large instruments, here's a video of the world's largest playable violin. It takes 3 people to play this monster: one to stop the notes, and two to draw the bow! It's tuned 3 octaves below the standard violin, meaning that its E string is only an octave above the bottom string of the double bass, and the two lower strings are off the charts. :-) Apparently, somebody actually composed a piece for this giant violin with orchestra!