[jr2]

Needed ingredients:
Diet Pepsi (not sure if other sodas will work, you can try)
Roll of Mentos

(spoilers are in black, select to see them.)
NOTE: Be careful.  The following experiment might make a mess.  You've been warned.
1. Open the coke.
2. half-unwrap the Mentos so that you can slide the whole lot into the soda at once.  (You might want to empty some of the soda out so it doesn't overflow)
3. Get someone to take pictures from a safe distance -> slide'm on in!  (Might want to do this over a sink, just so that if it does overflow, it won't get on anything   )
PS you might even be able to make a rocket with a smaller bottle or a constricted opening.  (Punch a hole in the cap & somehow get it on b4 it explodes)

[Turambar]

ah, the whole sugar-soda business

[aldo_14]

Strangely, we were attempting this at work yesterday with a can of Coke Zero and a non-Mentos product (to find out if it was Mentos-based).

[Prophet]

There are dozens of vids circulating around the net about this "phenomenon"...

[Ashrak]

brake.com search for coke and menthos

[Colonol Dekker]

Go into a pub and ask for a Guiness Shandy for the same result>> Ask noob barstaff straight out of school for the best results, Also to see if they are extra dumb,ask for it in a left handed pint glass, keep saying "nope thats a right handed one" to see how long they fall for it...

[Deepblue]

This is what the Chem teacher did on the last day of school. It made a huge mess.

[Goober5000]

I tried this a couple of weeks ago.  It was really fun.

[Skippy]

Does that work with any flavour(sp?) of Mentos?

[Wild Fragaria]

I tried this a couple of weeks ago.  It was really fun.

Did you drink it?

[Goober5000]

No, it was nearly all gone by the time the geyser finished.  We dumped the rest out.