I have found semi-documented proof on the fun you can have with microwaves!
If you see an old (Cold War-era) microwave at a garage sale, DO NOT let it go to waste! if it's cheap, buy it. Because:

1) if you have a flourescent light that fits inside of it, you can charge the lamp by placing it in the microwave and turning the microwave on! This creates a plasma inside (the guy who did this used an 8" bulb, and nearly was blinded as his kitchen was covered in immense, blue light).
2) if you have an incandescent lamp (light bulb), place it inside. The microwave will make all of its wires (not just the filaments) produce light. However, if left in for too long, it can start a fire and/or make the glass melt. Molten glass is a good conductor, so you might see some St. Elmo's Fire from it as the electrical energy is bounced.
3) i have unconfirmed (read: i don't want to ruin *my* microwave proving it) reports that if you take a grape, cut it down the center (leaving skin and only skin as a 'seam' between the halves), place it on a plate cut-side-up, and put it in the microwave, the grape will start sparking and explode! (unconfrimed; you can try it if you want and write up your results)
4) Place a lit candle in the microwave. Seeing as how fire is a plasma, and the microwave can create extremely powerful plasmas, it seems that when you turn on the microwave, the flame should get HUGE. However, i (being squeamish about setting fire to my family's kitchen) haven't tried it yet; again, you can put up your results here.