Over the last weekend my friend and I have been having tons of fun with a projector. We hooked up his playstation 2 with it and aimed it at the roof. However, the projector didn't have a stereo audio port. So I came up with a hack. We plugged the audio tulips into an A/V -> Scart converter, and plugged that into my little CRT television. Then, we connected the audio system to the headphone jack aaand... success!
I now have my commodore 64 hooked up on it and I must say, it's pretty cool. Gonna try this with my NES next week
edit: changed a kinda bad worded phrase (more like etiquette fixing but whatever)