I think those pesky aliens have already invaded earth by the time everyone realises 'cos a lot of weird stuff seems to be happening. Firstly, when Jeff Goldblum and his ex wife are talking in Area 51, she opens the fridge to take out something. If you look in the fridge, it's nearly empty....but when she goes to put it back again it is full of food! Secondly, when Goldblum (the one who has all the ideas) gets pissed off and kicks the trashcan, it flies out of the frame, and the camera swings away. When it swings back again, the trashcan is there again, seemingly having moved itself from off screen to where it was before!!!