Will Ferrell and Danny McBride can find the dumb fun in anything. Too bad that Land of the Lost is so much less than anything. It remolds a tacky 1970s TV series about humans in a cave-man time warp into a bloated theme park of a movie that features Sleestak sex, a dino-piss shower, bowel obstruction and the gayest of Chorus Line tunes (“God, I hope I get it”). McBride’s survivalist, Will Stanton, does weird things with fireworks. And Ferrell, as scientist Rick Marshall, reaches his hand down his shorts for a tug when things get boring. Kids, don’t try this at the multiplex. Director Brad Silberling, infamous for Casper and Lemony Snicket, repeats gags, like the primate (Jorma Taccone) grabbing the boobs of Rick’s British research assistant, Holly (Anna Friel), with laugh-killing frequency. You’ve been warned.