Depends how seriously you want this to take itself. If it's a serious musical, you're pretty much stuck with a love story of some sort (or basing it on Bible stories). Of course, you get a lot more wiggle room if you do a Gilbert and Sullivan-style comic opera, like Pirates of Penzance.
For best results, I'd definitely suggest the latter. Perhaps a story about a young naive remixer who's attending the first-ever OCRcon, trying to get his new crappy Geurdo Valley remix accepted out of pity by the judges by meeting them in person and convincing them he has testicular cancer. Somewhere he screws up and they find out the truth, but he ends up saving the day by thwarting Protricity, who showed up to ruin the festivities somehow. After that, djpretzel himself, played by Patrick Stewart, who up to that point had not been shown on stage, shows up thank our hero for his dedication to OCR. He still doesn't post the crappy ReMix, though.