Press the shift key.
Again.
Again. Again. Again.
Faster. Faster. Faster.
That's not fast enough. Try 15 times a second.
In many track and field simulations on video game consoles, the gameplay consists of pressing one or two buttons as rapidly as possible. In older games, it is possible to get 30 button presses per second by using the turbo feature of your controller. Most games sample the controller 60 times a second; apply the Nyquist-Shannon sampling theorem, and the highest frequency this can capture is 30 Hz. Newer track games keep out turbo cheaters by requiring the presses to alternate between two buttons, to be timed to a beat (Yo'ster Isle in Super Mario RPG), or both (upper levels of Dance Dance Revolution).
This gameplay system was adapted for use in Super Mario RPG for Super NES, Mario Party for N64, Metal Gear Solid for PlayStation, and WarioWare for Game Boy Advance. The newer games define a response curve that peaks at around 15 or so button presses per second, again to keep out the turbo cheaters. In Super Mario RPG, the faster you press the Y button when doing a fire spell, the more powerful the spell. In Mario Party and WarioWare, many of the minigames rely on rapid pressing of the A button (as well as rototorture, but that was eliminated in Mario Party 2; to learn why, see http://www.nintendo.com/home/features/caution.html ). MGS, on the other hand, places the hero in Revolver Ocelot's torture chamber; while it's eating at your health, you can press the O button rapidly to restore it. This, in addition to what it does to your hands, arms, and controller, is why it's called "torture."
How to survive torture (without turbo)
If you have to press one button, turn your controller so that the button in question is front and center. Place both thumbs on either edge of the button. Now rock the controller back and forth rapidly. If you do this right, you will press the button twice for every cycle of the controller motion. I get 15 Hz this way.
If you have to press two buttons, do the same thing, but place one thumb on each button. If the game accepts presses whether or not they alternate between buttons (as in Mario Party 2's wind-up helicopter race), you can become nearly 50% faster by placing one thumb flat across both of the buttons and the other thumb on one of them. This way you get A, A+B, A, A+B...
I'd provide illustrations, but E2 doesn't support outside links in any node that non-gods can create.