Biggest plot hole EVER:
Okay, here we are: Jurassic Park. We can make DINOSAURS! We even have a half assed explanation as to how we do it. But why the hell are some of the plants supposed to be from the cretaceous period??? What kind of mosquito sucks blood out of plants???
To be fair, I can talk about Jurassic Park and plot holes for ever but you'd get bored.