Split between four cities with each of them having multiple sites means that socially De Montfort is a bit of a mess. Four out of the eight sites have something to offer in the way of evening entertainment and the main Students' Union is on the Leicester campus. This is the only one that has a night club and late licence every night.
Each of the cities has a De Montfort Students' Union facility so even if there isn't one at your site, there will be something nearby.
All of the bars have promos and activities of some kind so you shouldn't be completely bored but make sure you check carefully where you are going to be studying as the social experience can be very varied. (Scraptoft is pretty poor for example.)
Big Cheese and Kinky Afro are offered by the main union and seem to go down pretty well. Leicester puts on big gigs at The Arena which attracts some huge names and is one of the best student venues around. Other good places include Kudos (club), Russell's (bar) and Gold's. Bedford and Milton Keynes have late licences on Fridays which keep things going until 1am.