We did something fun, geeky and completely British last weekend- we ended up at a meeting of model steam tractor enthusiasts.
I didn't take these pics, just found them on the web, but it's what I'm talking about. There were about 20 guys like this, all riding these tiny steam tractors around.
For anyone near the south coast, I'd recommend a visit to the Hollycoombe steam collection in Liphook. They've got a collection of steam powered fairground rides that you can ride all day for the price of admission. Best to go on a sunny day.