The Definitive Movie Rulebook

2. Never FUCK A STRANGER IN THE ASS!

Otherwise things will happen.

3. Never feed them after midnight.

4. Nuking the site from Orbit...

...it's the only way to be sure.

5. Don't look at the Ark of the Covenant. Keep your eyes shut!

7.  Sometimes you just gotta say, "What the fuck!"

8. If someone asks you if you are a god - you say yes.

9. Your first shot puts him down, then you put one in his BRAIN.

Then he's dead.

Then we go home.

10.  When this baby hits 88 miles per hour, you're gonna see some serious shit.

11. Don't concentrate on the finger, or you will miss all that heavenly glory.

12.  15 years of imaginary training CAN be put to use.

13. Shoot the hostage.

14.  Always bet on Black

Was going to post this link, but instead I'll simply say:

15. "Rule No. 1, Cardio."

16. You don't talk about Fight Club

17. "Leverage! Leverage! YA GOTTA HAVE LEV-ER-AGE! Did I mention Leverage?" - BATTLEFIELD EARTH

18. Always Be Closing

19. Never rat on your friends and always keep your mouth shut.

20. If you need a boat, choose the bigger one.

21. It's the car. Chicks dig the car.

22. Never go in against a Sicilian when death is on the line!

23. They pull a knife, you pull a gun. He sends one of yours to the hospital, you send one of his to the morgue!

24. Never rub another man's rhubarb!

24.  Greed, for want of a better word, is good.

25.  Never tell me the odds.

26. Do NOT say "what" again, motherfucker.

27.  Under no circumstances whatsoever is Baby to be placed in a corner.

28. You can't give another man's wife a foot massage.  Or can you?

29. Whatever doesn't kill you, simply makes you stranger.

30.  Serve that revenge cold.  

31. You CAN slip out of handcuffs, but only when it is funny.

32. It is bad, VERY bad, to steal Jobu's rum.

33. Aim for the nerve stem, to put down your basic Arachnid warrior for good.

34. Just put on the sunglasses!!

35. "Squeeze, don't pull."

36. When you shake Sinatra’s hand. You should know better.

37. Do or do not, there is no try.

37.  Don't be mean because, remember, no matter where you go, there you are.

39. Never get out of the boat.

40. Don't touch it. Just listen to the sustain.

40. "He who can destroy a thing controls a thing."

NB: Leaving this as 40 since Ken already posted Art's 39 pick.

42. Never touch a black man's radio.

43. You cannot make friends with the rock stars.

44. Some motherfuckers are always trying to ice skate uphill. 

45. If you have no short-term memory, always carry a pen & paper.

46. Choose wisely.

47. No women. No kids.

48) Evil will always win because good is dumb.

49. Put your seatbelt on, boy. I don't ride with anybody 'less they wear their seatbelt.