Not many people get excited about a census, but we do at MyHouseMyStreet, and there's one this year! We see it as a link from what we're doing now back to the first census in the early 1800s.
MyHouseMyStreet uses information from census returns (among other sources) to explore the details of Brighton and Hove's former residents. They remain confidential for 100 years, so the most recent one available is 1911.