Le Mans is highly recommended. Not just for the racing, really, which is interesting only for the first and last couple of hours, and fascinating to see at night if you've never seen motorsport at night. It's the collection and variety of petrol heads that you meet.
I took the Westfield there a month or two after I got it on the road for its' maiden trip and the cameraderie as I stopped off at each petrol station to
plug up the oil leaks and pray that it would get me home again take a break was fantastic. From those driving everything from frogeye sprites to blower bentleys to modern supercars. There's a bit of everything there.
Camping at the circuit is not for everyone, TBH. It's dusty, smelly, you can forget having a shower all weekend and trouble is not unknown. We've camped here
http://www.chateau-de-chanteloup.com/ in the past and it's a great camp site maybe 15 minutes drive from the circuit but much nicer facilities. Have a look at their "24 heures" page and you might spot a familiar face.
He does fill up quite quick so it's worth booking well in advance. Ditto for the ferries / tunnel which get quite expensive at the last minute. If you're not bothered about a grandstand seat you can just turn up at the track and get a ticket, or buy online in advance for a bit more convenience.
I'm seriously thinking about doing the Classic Le Mans this year if anyone's up for that?
http://www.lemansclassic.com/uk/index.htmlKevin