Games are, in terms of actual input, inherently repetetive. What makes them unrepetetive is the situations you can find yourself in. Sim City is the same basic thing over and over - building and zoning. But building a small scenic town brings completely different challenges to building a huge CBD, so the game doesn't feel repetetive.

Of course, if something's insanely fun, repetetion isn't necessarily a problem. Something like Dynasty Warriors, for instance.