Mythbusters - Postbuster(Busters)

Postbusterbusterbusters

Except that this implies the person sleeping was able to refrain from any sort of movement through an entire night's rest.

ANY SORT OF MOVEMENT including the accidental deduction of applied pressure. In other words, this person must sleep in a solid state, completely unmovable and without fidgeting.

All of that, of course, assumes that the poster did not sleep on the keyboard. Because then there'd be more keys than just the 'f' key.

From this we can draw that it's likely the person fell asleep leaning away from the computer and keyboard, and somehow managed to maintain the same amount of pressure they had as they started sleeping.

I highly doubt anyone is capable of this.