I'm not sure if this is the right place for this, it might be more noticeboardy than talky, but going by what seems to be the reputation of Wimpole I think it will interest a lot of people around Cambridge and it's not as if we're swamped by active threads.
Lurking at the bottom of today's email from Mumsnet is news of a deal whereby you sign up to the jolly interesting MyFarm project for £15 and as part of your membership receive a family ticket to visit the very excellent Wimpole Home Farm.
It normally costs more than that for two adults to go, unless you are National Trust members, and the family ticket includes at least two (it may have been three) children, so it's a good deal even if you don't get much involved with the forums and voting and what-not.
Wimpole Home Farm is completely great - loads of animals up close, little ride-on tractors, lovely countryside and parkland, even the odd slope. If it were even remotely accessible by public transport I'd be there every week.