writes "Everyday objects can produce interesting effects when you stick them in a standard microwave. Grapes spark, matches create superheated plasma fireballs, mini lightning-bolts arc between sheets of aluminum foil, and soap both splits open and puffs up, creating a somewhat vulgar spurt of bubbly excrement that has to be seen to be fully appreciated. However, as cool as microwave experimentation can be, balls of plasma and the like are bad for both your eyes and your microwave, so it's probably best not to try these things at home. update
This site apparently is behind a really nasty popup that I missed (yay Firefox) the first time through. You've been warned... here it is
but given the overall rottenness of the pop-up, I guess I wouldn't bother. Some folks know no shame. My apologies to the readers.