I live in St Andrews, Scotland but was born in Newcastle, England (I'm going to give the Scottish perspective).
I love haggis, which is chopped up and spiced offal from a sheep. It sounds disgusting but it's actually a lovely, savoury taste.
I'm a university student, so most types of modern music are popular among my friends. Look at the UK Top 40 singles chart for an idea of what's popular here.
Guy Fawkes Night (celebration of the failed assassination attempt by Catholics on King James I in 1605), our four national days (St George's Day - 23 April, St Andrew's Day - 30 November, St David's Day - 1 March, St Patrick's Day - 17 March), any royal holidays we have (weddings,coronations, jubilees). Scotland also has Hogmanay celebrations at New Year and Burns Night in January which celebrates the life of writer Robbie Burns.
We obviously don't celebrate things like 4 July, Presidents' Day, etc. your Veterans Day is much less of a deal than our Rememberance/Armistice Day (11 November) when we remember our war dead, especially those who died in World War I, by wearing red poppies on our coat lapels and attending remembrance services around the country. Generally there's a minute's silence nationwide at 11am. We have a few Christmas traditions that you don't - Christmas crackers, the Queen's speech, Christmas pudding. Easter is also slightly more important of a holiday here and usually means two weeks off for school kids, and two days off for adults. Our Mother's Day is a couple of months away from yours.
I like our understated, reserved nature and the way that people 'get on with it' in Britain even if they are quietly complaining. I also like how receptive we are to foreign cultures, our proximity to Europe and our global cultural reputation.
Standard young people things really, depends on the person. They go to gigs, play video games, go to the cinema, to restaurant, they travel. One big difference is that most people under 23 in the UK can't afford a car, or don't have a driving licence.
Weddings are similar to yours as you get your traditions from us. We tend to dress a lot more formally (men wear morning coat, waistcoat, cravat, top hat and a flower). Births and deaths are largely the same, except we don't often do the whole open-casket funeral thing you do.
Often perpetuated by Americans...bad teeth, 'soft' or effeminate, that England = Britain, etc.
Don't talk about how quaint everything is or patronise us. Visit some major cities and some small places too. Don't forget Scotland!