I have a good candidate: 1987 Bally Party Animal, there's a large rubber along the back, just up against the back wall and underneath two sets of ramps. To replace, you have to remove all ramps, the two posts holding the rubber, pin the rubber up against the back wall to prevent it from releasing itself, and then put the posts back in under tension. Yuck.
Anything that requires removal of ramps or toys is no fun, though it's usually cheap enough just to do everything at once.