Ever heard of the band Sparks? If you haven’t, you’re not alone. If you have, it’s not unlikely that they’re one of your favorite bands. The pop rock duo formed by brothers Ron and Russell Mael has in their five-decade run gained a cult following of some seriously creative people, from Beck and Weird Al Yankovic to Mike Myers and Amy Sherman-Palladino. And they are the subject of “The Sparks Brothers,” a new documentary from filmmaker Edgar Wright that explores the question of how a band can be “successful, underrated, hugely influential and overlooked all at the same time.” The film premiered Saturday at the Sundance Film Festival.