MB I don't much agree with you about being limited to what one's parents find interesting. My ds is just 4, and I have already found myself having to keep one step ahead of him in various topics that he is interested about and I have no clue about.
I am also amazed at the breadth and variety of experiences that we have together in a typical day just from wandering about together looking at things and talking to people. We have recently watched and spoken to:
tree fellers working on some willow trees
a man fishing
an artist who climbs buildings around Europe as performance art
a textile artist
a woman with epilepsy who uses an assistance dog
a horticulturalist.
None of these are areas that I have a particular interest in (in fact I would have said I did not WANT to learn about fishing, for example, but in actuality it was very interesting and I learnt new things).
We learnt quite a lot on each occasion either from speaking to / observing the people and from following up ds's questions afterwards, via the library, internet, etc
I think the community we live in is an incredibly rich source of education and that unless you are keeping your child away from the community in some way, that they will find their own interests, and that those may not happen to be the same as yours.