If you take a 2 little bottle of Diet Coke, put around 6 Mentos in the bottle. The coke erupts out from the bottle like a geyser. Need to try it.
There are dozens of videos on http://video.google.com
My favorite:
Google Video 1
Created a fountain using 200 litre of Coke and 500 odd mentos. These people have done crazy
http://eepybird.com/dcm1.html
And these are extremes!
Google Video 2
These are making ice bombs!
Google Video 3
