Orchestra:
Accordian:

One Guitar:

Two Guitars:

11-String Bass:

Contrabassoon:

Balalaika (Russian folk guitar):

Alto sax:

Ball-point Pen:

Beer Bottles:

Beatboxing Flute:

Ruler:

Tesla Coil:

Update: I had posted the wrong video for Beatboxing Flute. The video is fixed and I added 9 more videos. (New videos taken from here and here)

All stolen from the Neatorama blog post about fun facts about Mario: