Before the phrase “It’s like trying to herd cats” was common in the American lexicon, Gregory Popovich was learning to do just that while working as a clown in the Moscow Circus. He brought his comedy-magic-animal act to Vegas a decade ago, first at the Circus Circus Midway, and today is featured at the V Theater at the Miracle Mile Shops at Planet Hollywood. Popovich has developed a family-friendly afternoon show by watching ordinary house pets (most of whom Popovich has adopted from local shelters) perform mind-blowing stunts. One example: A cat sits atop a dog while the dog pedals a tricycle.