This is cool

The light bulb in the microwave oven. You can take an old one, it doesn't have to function anymore to give the desired effect. However, the glas has to be intact so the gas is still inside. I noticed that small bulbs won't work. I used a 230 V / 60 W one. Again you won't believe what you see ! All kinds of colors coming out of the bulb. But you should take care here. Sooner or later your bulb will explode. I tried mine for 10 seconds, let it cool down (probably not enough) then I tried it for another 10 seconds, let it cool down (probably not enough again) and then after 2 seconds after turning it on again it exploded inside the oven. The door of my oven was way thick enough, so all glass stayed inside. It's quite easy to clean up the glass and I don't think it will do much harm to your oven. However, my second lightbulb never exploded! The glas gets very hot but it won't blow up!
From 2 people I received the tip to put the bulb in a bowl of water in the microwave oven to cool it down so it won't explode. It works but the bulb might receive too little energy to light as brightly as it does without water around it.
I haven't tried small fluorescent lamps and flash bulbs from a photo flasher yet (because I don't have them) but I expect them to be very nice, too. If you try one, please let me know the results.