Last year at Free Press Summer Fest, we saw Stars haul out this little thingy that was basically a tiny keyboard with a mouthpiece you could blow into. It was the first time we'd ever seen a melodica played live. Since then, Rocks Off been kind of obsessed with weird, custom instruments.

Here are five of the most unusual.

The array mbira was invented by a guy named Bill Wesley, basing it on the design of a Zimbabwean instrument called the mbira. Did you ever run across one of those coil-spring doorstops when you were a kid and spend an hour or two plucking at it because it made such an awesome boinggggg?

Well, the array mbirra works on the same principle, with flat, rounded carbon springs bolted to the instrument and plucked in a similar manner. It kind of sounds like a snappier marimba.

Who Plays It? Imogen Heap (fast-forward to 2:20 to see her play it); Ry Cooder.

Based on the ages-old principle of filling many glasses up with different amounts of water to get a chromatic tone scale, the glass armonica is perhaps the most uniquely American instrument on this list because its standard incarnation was invented by none other than Benjamin Franklin.

Yes, just like the alpha-bro douche who hauls out his guitar at every party and plays Sublime covers to impress the frat girls, we can't help but imagine Franklin wheeling out this bizarre cross between a sewing machine and a pottery wheel and bellowing "Who wants to hear the latest Joseph fuckin' Haydn jam, bitches?" before sitting down and wailing away on this spinning column of glass bowls while nearby ladies swooned and Thomas Jefferson and John Adams rolled their eyes.

"Oh and by the way... I invented this thing. That's right." That Ben Franklin was one smooth operator.

Who Plays It? Tom Waits, Damon Albarn, one of the original authors of the American Constitution... ladieeeees.