Fascinating.

Click this link.
Watch the videos.
Be entertained for an hour or two.

[video=youtube_share;7lAOOwMNodA]http://youtu.be/7lAOOwMNodA[/video]

Me and a friend used to do the soap in the microwave thing all the time when I was younger. My folks would always get pissed off because all the soap would be missing, only to be found later in a flat pile of goo on a paper plate.

Try grapes. They tend to pop around and sizzle loudly.