18. Dirty Grandpa
Box office: $35.6 million
Playing the randy grandfather, Robert De Niro is a hoot as widower Dave. He has the hots for co-ed Lenore (Aubrey Plaza), whom he meets on a road trip with his grandson Jason (Zac Efron). Against Jason's better judgement, they follow Lenore and her girlfriend Shadia (Zoey Deutch) to spring break in Daytona. In a party scene, Lenore hits a plastic bong and blows the smoke into Dick's mouth. Aghast, Jason asks, "You're smoking grass now, grandpa?" Dick shows him a piece of hash. "Lebanese red," he brags. "I have some of this leftover from my time in the Middle East." But it's a gateway drug, Jason persists. "You just opened a gateway to being a pussy. Take some!" Another highlight is Tan Pam (the Daytona drug dealer played by Jason Mantzoukas), who brazenly announces, "Let's celebrate by buying local drugs from a reputable local drug dealer."