For sheer summer escape, it's hard to beat a good zombie flick. Good, bad, always ugly, the undead are a highly amusing genre as a whole. "Zombieland" from 2009, with Jesse Eisenberg and Emma Stone riding shotgun and Woody Harrelson wielding one, remains my favorite. "Warm Bodies," a clever hipster twist on the old trope starring Nicholas Hoult and Teresa Palmer out earlier this year, comes close. But for now, consider indulging in the campy, eco-eccentric fun of Brad Pitt's battle with the undead, their teeth-chattering and bad hygiene giving "World War Z" its bite. And don't let the environmental message scare you either. Director Marc Forster understands it's the absurdities and the oddities that bring zombie movies to life. Something — virus, plague, aliens, a studio exec in need of a horror film in his portfolio — is causing the undead to rise in "WWZ." They have a swarming tendency, making giant hills of undead bodies with their undead buddies. So cool. The best is when they hit a wall. Ah, zombies, always a message for the living in the undead.