There are a couple of common celebrations in Britain which you may not be so familiar with: Guy Fawkes Night and Remembrance Day, a.k.a.* Poppy Day. The former is celebrated on November 5th, the latter is on November 11th. To find out why, just follow the links from Wikipedia above.
This is a video of the Guy Fawkes celebration in Victoria Park in London. Enjoy! You can also visit our post last year here.
* also known as