Years ago, when I was playing SMB on the SNES, I made up words to go with the Mario theme. And then I would sing them while Mario was battling the Koopas at the end of each round. LOL This is probably something I shouldn’t ever admit again, though. 
“His name is Mario and not Luigi … he was a fool-a for Princess Toadstool …”
(a small sample … and no, I do -not- have a sound file of it!)
There were 5 of these events, actually, each a few years apart. Each one had a live orchestra play various game music tracks, and there’s a CD for each of them. Unfortunately, they’re impossible to find nowadays, but if you look hard enough, you can find mp3s of them. More info here.
There have been numerous other similiar events where they orchestrate game music, including a recent one where a band called “The Big Band of Rogues” did ska/jazz arrangements of Mario and Zelda music. Game music is a lot bigger in japan than it is…outside of japan.
You know, I think they used that orchestral version as some of the music at Japan’s entry in the SAQ fireworks competition here a few years back.
That’s nice, but what I really want to hear is the Metroid Brinstar theme on a guitar.
A couple of years ago I was working at a summer camp when a coworker of mine started humming the SMB theme. We all thought it was great, but the kids we were teaching didn’t get it… they must’ve been about 9 or 10. I didn’t realize that SMB was starting to turn into a generational thing.