I think the game I played most for the C64 was called "Donald Duck's Playground". The objective of the game was to eat as many watermelons as possible off a conveyor belt, it was pretty ridiculous.
Not quite. :D The objective of that game is to earn money to buy slides, swings and other toys for his nephews' playground. Donald has four different jobs to seek:
* Working at the railway, routing trains to different stations
* Working in a toy store, putting toys in their right place
* Working at a fruit distributor, sorting (not eating!) fruit
* Working at the airport, sorting outgoing goods in the right boxes
You determine for how long each job will last, and do your best to earn money. Then you cross the street and walk into three different toy stores operated by Mickey Mouse, Minnie Mouse and Goofy, spending your hard earned cash on playground stuff.
Basically it is an educational game for children, learning how to count money since you get to do all the cash transfers and exchange yourself. Well, the children also learn that you have to have a job to get some money...
BTW, M.U.L.E. is a big favorite of mine too and played a lot.