Yogi and Boo Boo are two bears living in Jellystone National Park (the fictional version of Yellowstone). Yogi is usually dragging Boo Boo into some scheme to get them in trouble. Most of the schemes involve stealing picnic baskets. If they aren't stealing picnic baskets they are trying to escape or somehow bothering the campers. The man in charge of stopping them is Ranger Smith.
Yogi first appeared on "The Huckleberry Hound Show" in 1959. He became so popular that they decided to make a show about him. The character Cindy Bear was added later as a love interest.
This is a great series. If you have children I would suggest buying the DVD's. This show is truly a lot of fun.