“Scary Movie 3” is certainly a movie, and it’s the third in the series begun by the Wayans brothers and now taken over by David Zucker (of “Airplane” and “Naked Gun” fame). It isn’t scary, of course, but that comes as no surprise. The problem is that it’s not very funny, either.

Apparently working on the assumption that most of today’s moviegoers wouldn’t get references to anything they haven’t seen within the last few weeks–an assumption that, sadly, is probably correct–the scripters have made this installment a combination sendup of “The Ring” and “Signs,” pointlessly mixing in–solely to pander to the core urban audience, one supposes–a generous helping of “8 Mile.” (Stray recollections of a smattering of other recent flicks, most obviously “The Matrix,” intrude occasionally, too.) All of this is given the usual contemporary treatment–most of the gags involve sex, slapstick violence, flatulence, excrement, or nudity. Tastelessness is de rigueur: particularly charming are throwaway bits regarding pedophile priests and the physical abuse of disabled people (a sketch that also features a photo of Mother Teresa blown up by a shotgun–funny stuff). Simply put, to call the humor sophomoric would be an insult to second-year students everywhere.

The cast show a willingness to go along with the stupidity and humiliation. There’s Charlie Sheen, in the Mel Gibson role, playing blank and befuddled with obvious ease; and Anna Faris, bubbly and bland as the TV reporter caught up in “The Ring;” and, perhaps inevitably, Leslie Nielsen, looking wizened and bent of knee but still game as the president, even though the material he’s saddled with is particularly lame. Unfortunately, Simon Rex, in the composite of Joaquin Phoenix “Signs” part and Eminem’s “8 Mile” one, makes for a particularly dull “hero.” A small army of others–Regina Hall, Jeremy Piven, Queen Latifah, Eddie Griffin, Anthony Anderson, Camryn Manheim, George Carlin, Ja Rule, Simon Cowell–make appearances of various lengths; they manage to get through their pedestrian material with straight faces, which is about all that’s expected of them. Unfortunately, we have no trouble following their example.

This “Scary Movie” has very little in common with the first two Wayans installments, which isn’t a terrible thing since they were no great shakes to begin with. Unfortunately, the Zuckeresque brew offered here instead is far too stale and puerile to generate much besides groans.