My favorite is still the single screen version of Mario's Cement Factory. Played it so much, I rolled over the score twice one day.
Ended up doing tricks to make things more interesting, like overflowing the bottom cement receptacles, and running down to the lower level to pull the lever just before the cement falls. It's not that hard on the left side if you time it right with the elevator, but the right side is trickier since both elevators need to align just right.
Got a version of the game on my DSi, but they altered the score to have more digits, so I doubt I can do the roll over.