Lego Harry Potter was great. You could take control of the world famous wizard-kid and all his mates and zap the shazam out of almost every object in the world. Whether it was a pot plant or a ghost, targeted items and people would react in hilarious and unpredictable ways. The pot plant would grow to a monstrous size and swallow a nearby student, the ghost would start singing opera. Mix that sense of playful exploration with the Lego games' trademark brand of silent, slapstick humour and you had something rather wonderful.
