Go from the pits witth any road car, stop somewhere, change to neutral gear and press the ignition button to turn off the engine. Then change gear from neutral to e.g. 1st gear (without the clutch), it will stay on neutral. But: Change gear without the clutch to 1st and then press handbrake - it will change the gear to first. Works with all the gears (1st - 6th).
EDIT: Change gears without the clutch!
EDIT: Change gears without the clutch!