HAHA.... my son is doing his science fair project on this very thing. It's cool, and works great with rootbeer too (but it's a waste of good rootbeer).
Oh, and I also decide to try the eat mentos and chug soda, well actually, I put soda in my mouth and tried (yea, only tried) to put 3-4 mentos in my mouth.... It spew everywhere and out my nose too..... it was really funny, too bad the video camara was nowhere around....