Only because it's one of my obsessions in life, I'd go check out a rugby game if you know of any going on. Seeing as Egham is in the west end, I'd go see London Irish at the Madjeski Stadium in Reading. Apparently they put on a good show at home, and they're not doing to badly this year (bonus if you were to see them against London Wasps, Leicester Tigers, Sale Sharks).
Even if you're not well versed in the sport, I'd still say check it out. It's a great atmosphere with more families and respectful (people still shhh chatterboxes even when the away team kicker is setting up!) fans than soccer matches, but still a with lively spirit. Chanting and songs are common, beer flows, and the pies are good on a cold day. I was shocked to be part of a half time 'sing along' at Memorial Stadium in Bristol where thousands of people were singing popular songs at half time. NEVER see that in Canada! Then after the match (any match) pop into the pub to have a few, chat with the locals, and even get to run into the pros. There's a massive Canadian, Phil Murphy, who plays for Irish. Not sure of their policy, but at Bristol the players stay in the clubhouse until 7pm to chat to fans, etc. They're the model of how pro athletes should be!
Anyway, have a good trip.