This was more for the men in our party than the females, but we all had a pleasant few hours going round.
Coming from Abingdon, we always have a look out for MG's, and they had a hall dedicated to MG's and Morris which we were pleased to see, the story about Rover was their Birmingham factory not Cowley though. They also had a red room, and who doesn't love to see classic red sports cars and everything in between.
One for the kids was finding the cars from Back to the Future and also ghost busters (along with a button to press for the music).
Adults loved the display on the "advertising of motor cars", is your wife stuck at home all day with the children while you go off to work with the car... buy her a car!!! couldn't do that today.
All the cars had a really good detailed descriptions beside them, not just the boring petrol head stuff but what TV programmes it had appeared in (usually Top Gear), how long it had taken to restore, how often it races etc.
Quite a few bits to keep children amused whilst going round, and also an outdoor play area. Plenty of space for pushchairs and baby change facilities. There is also an on site cafe but we didn't go in. Their website can be found here http://www.haynesmotormuseum.com/