Sorry to dig up a several day old thread, but this was the closest I could find to what I was looking for and didn't think my contribution was worthy of an original thread 😛
I was just digging through the MP3 server at work and came across some old Richard Cheese stuff. I forgot how funny some of it was. His version of NIN's Closer is absolutely hilarious! I love the whole cheap, Casio keyboard sound. If you don't know who he is, he released an album a few years ago called "Lounge Against the Machine." It covered top songs of the late 90s and 2000 done in lounge singer style. They were also the house band on that karaoke show on MTV for awhile. Extremely funny IMO.
More seriously though, I know some philharmonic or pops orchestra did a performance on Metallica stuff that was made into a CD several years ago. My friend's roommate had it in college and it was actually quite cool. For some reason I think it had something to do with San Francisco (either recorded there or the symphony was based there.)