Steppers are motors that move in discrete steps. You can control them to move a given number of steps without any feedback. You can rotate them slowly but with a lot of force without using any gears.

See full description of the project (which includes a video) to learn how to integrate a common stepper motor into a NXT creation and how control it.

My controller was influenced by a stepper controller that Michael Gasperi posted to one of the forums. See the forum for the Michael’s circuit and program, and click here for a video of his stepper in action.