Weird noises are what I live for. Here are a few worth trying out:

1) Use your pick to flip one string over the next highest one at the higher frets (about 10 and up). Fret both strings behind the point where they cross over, and make sure you're holding them tight in place. Then use your pick to play the spot where they cross over. It sounds a lot like a bell. This works best on the lower strings, with your neck pickup activated.

2) Point any type of remote control at your pickups and press some buttons.

3) If your neck pickup isn't set too low, just push your low E string downward so that it touches. Add a little reverb, and it sounds like a radar blip on a submarine.

4) Pull your high E string downwards (away from the neck) and then back towards yourself. I'm told if you have a scratch plate on your neck pickup, it makes a dolphin-like sound, but seeing as neither of my guitars have scratch plates, I can't verify this. Also, be careful not to break your string. :)

5) Mute the strings with your left hand (just by placing them across all of them without applying pressure), then get a golf ball and touch the unwound strings one at a time at different frets. It makes these cool computer beeps. It basically works on the same principle as a slide, but slides are near impossible to get to touch only one string at a time.

I didn't make those up, by the way. I got them from some website long ago whose name I cannot recall. I personally find that the coolest noises come from feedback plus certain settings with my pedals. One time I got my DS-1 and Big Muff to this point where certain notes sounded like my wah was on or something. It was awesome.