What do a parent writing an insult on their son in poop, a young boy calling 911 because his date’s having her first period, and a man’s bowels exploding when he gets hit by a car have in common? That’s right; none of these ideas are even remotely funny. Also, they’re in “Movie 43,” one of the most desperate, vacuous and screechingly unfunny films ever devised. The only person in this star-studded cast who somehow managed to escape with their dignity intact is Dennis Quaid. Nobody else does. Not one. This is more than just an unfunny comedy; it is a comedy void. Its reputation is not unwarranted; it truly is as awful as you’ve heard.