i did this for DH, he did enjoy but it wasnt what we expected- loads of people- like hundreds- and there was quite a push once there to buy a drive in another car/dvd of drive. was fairly short really for the money...
I got DH a day at Silverstone for his 30th - much cheaper if you book direct with Silverstone rather than one of those people like Red Letter Days (although they went bust didn't they?). I couldn't decided whether to get him a track day or an off road day, so I got him a long day that did a bit of everything, but got all the rest of the family to chip in. from memory they did:
Track racing (solo) Porsche racing (with drivers) Off Road land rovering Rally driving Caterham skills
I'm sure there were a couple of other bits too. Good support/transport around/hot drinks for spectators.
Oh yes, and the package came with tickets to any Silverstone event apart from the British Grand Prix. We went the the Mini Grand Prix!