This scene is done for the contest in 3dtotal.com , ‘Speed Modelling’. Whole scene is made in 20 minutes, except textures and lightning. They took nearly 10 minutes. Let me tell you how this thing works:
When mouse enters into the box and touches the cheese, the cheese rises and that 1 kilo falls down, closing the door. The mouse is trapped! With this trap, we also save the cheese. 
