I have seen a lot of the Fantastic 4 cartoons and enjoyed them. The movie making effort was always going to be challenging; but I think they did a decent job. Nothing great, but definately above average.
It all starts with a freak accident at a space station. Everyone aboard gets exposed to the radiations from a space storm and their DNA undergoes some changes to give them all super powers. You have Mr Fantastic who is flexible like rubber, The Invisible Girl, The Human Torch and The THING ( the one most affected, because unlike the others he always looks UGLY ;) ). The Evil owner of the space station, Van Doom also get exposed to the radiations and gets transformed into some hard, magnetic metal; he is capable of absorbing any kind of electric power and use it against his enemy.
So starts the battle between Good and Evil. You do learn some Science 101 too :-) .
You should watch it atleast once in the theatres. On the TV at home, I am not sure you’ll feel the same effect.