Remember when games had conveyor belts in'em? Hell, just about every platformer had one (or twenty). One would send you right, the next one takes you left. And in many cases, the belts usually led to a pit or bed of spikes.
Metal Man's stage in Mega Man 2 is one I'm quite fond of. The belts would actually switch directions on you in some places.
Are there any memorable stages you can conjure up that featured conveyor belts?