As I explain to my classes - why do they need a break on the last day of school when they are about to have two weeks off? If I make them work then they will appreciate their holiday all the more . As other posters have said, students do get bored with DVDs in every lesson so they appreciate something different to do. Make sure it's something they can just get on with though. Trying to stand at the front teaching would put you onto a loser.