Sinking cupcakes. :[

[xbad_candy]

Oh how I dream for fluffy round top cupcakes. I know it can happen. My cupcakes come out of the oven puffy and pretty, all rounded on top. Two minutes later they've fallen flat into themselves.

Still delicious, moist, and fluffy on the inside, but not nrealy as pertty. What can I do to prevent this from happening? Is there anything?