Been to the Pitt-Rivers museum several times with GSs. It's attached to the Natural History Museum in Oxford and the boys enjoy visiting both of them. the anthropological collection in the P-R is immense. Need I say that the two boys like the various kinds of weapons? I love In Our Time, even when a lot of it is over my head!
The DGS absolutely love the Pitt Rivers as do their parents and grandparents. Yes, the In Our Time programmes are excellent. The ideal of Reithian broadcasting and a strong argument against the lobby that thinks information should only be offered through the medium of slapstick.
I live in Oxford so get to the Pitt Rivers as often as possible. It opens at rather strange times but never quite long enough to 'do' it in a day - the shrunken heads alone take a good 15mins to mull over. It's a lovely place and not as crowded as the Ashmolean - recommend for a great day out, and the Parks are close by, so can combine a picnic (I'll stop now as I'm starting to sound like a travel rep!)