This reminds me of when my chemistry teacher told us about how, as an undergraduate, he did this experiment:
[video="youtube;ezsur0L0L1c"]http://www.youtube.com/watch?v=ezsur0L0L1c&list=TLaPEtGT24T9c[/video]
But apparently he underestimated how much foam it would produce, and he also did it in a fume cupboard. You can imagine how that turned out...