By the prehistoric program痴 fifth year, Pebbles (born in the third) and Bamm-Bamm (adopted in the fourth) can walk, but they can't yet talk--although they sure can babble. Well, who needs talking toddlers when your son is the strongest in the world? In the season premiere ("Hop Happy"), Barney Rubble (Mel Blanc, sounding a lot like Dustin Hoffman) decides to purchase a pet for the powerful kid. After all, the Flintstones have Dino, and there's only so much of the purple pup to go around, so he brings home a "hopparoo" named Hoppy. Another fifth season highlight is "Monster Fred," in which Flintstone (Alan Reed) is bopped on the noggin with a bowling ball. Barney takes him to a Dr. Frankenstone who switches his personality with Dino's. Then he switches Fred's with Barney's--and that's just to start. There are a number of other monster movie/television show parodies. In "A Haunted House is Not a Home," Giggles Flintstone names Fred his sole heir--if he値l spend a night in his eccentric uncle's spooky mansion. Then in "The Gruesomes," diminutive Weirdly and willowy spouse Creepella move in next door. Heck, they even have their own TV show. As usual, the pop culture references and goofy puns are half the fun, as when Fred refers to a certain mop-topped quartet as "The Bagels." Several episodes later, the Stone Age band are introduced as "The Four Insects." Their specialty? Why, "bug music," of course. Then there's the time Fred and Barney appear, as a ventriloquist and his dummy, on "The Ed Sullystone Show" ("Itty Bitty Freddy") or when they find themselves in the middle of a real-life "Jay Bondrock" movie ("Dr. Sinister"). This four-DVD boxed set features all 26 episodes from the 1964-1965 season--each one "a page right out of history!" --Kathleen C. Fennessy