Help for DH's 30th birthday - daytime fun!

[sleepychunky]

Hope you can help. DH is 30 on December 8th. I've booked the day off work, so has he and I've told him I've got something planned. I haven't I thought we could go to Chessington for the day (we both love the rides and have childminder looking after DS) but it isn't open.
Any ideas for something we can do in the daytime, in Sussex/Surrey/South East (not London because we both work there and it's not particularly special for us iykwim)
which will be a bit different?
For his 21st I bought him a rally experience day at Brands Hatch, which was great, but haven't got too much cash to spend this time.
Any thoughts

how about 'go ape' , high wire thingy, look on the web, theres one here in bracknell hth

Thanks but it's not open then either

Paintballing?
Go Karts?

Maybe good old fashioned day out in Brighton? Funfair at the end of the Pier is always open, followed by fish and chips on the seafront and maybe candyfloss after? Stick around and see a show/alternative comedy in the evening?