Alright. So now as I type this message I am drinking some very minty tasting diet pepsi... let me explain. I saw this clip on google video and decided to give it a shot. There was a kid in the clip who decided to drop a handful of Mentos into a liter bottle of diet Pepsi. The result was a friggen geyser of pepsi that went to the ceiling. I went and bought a two liter and a box of mentos and tried it outside. I too got a tower of 6 foot tall pepsi stemming from the bottle. Was pretty damn cool although it emptied about a liter and a half of the bottle. The thing is i am quite curious as to what happened. If anyone has an idea please let me know.