In the future (after the apocalypse, I'm assuming), leather-clad gangs will battle for supremacy on the rubble-strewn streets of New York City. They will carry torches (perhaps the sun has been blotted out?) and scowl a lot. There also will be a whole lot of overturned/ burned-out vehicles, as is to be expected in any post-apocalyptic scenario. The future, it turns out, is vaguely reminiscent of "300," or maybe "The Warriors," or both. That, in a nutshell, is the basic scenario of "Run This Town," the much-anticipated video that brings together three of the hugest names in the music industry — Jay-Z, Rihanna and Kanye West — and casts them as warlords in a 23rd-century turf war. Anyway, here's what you need to know about "Run This Town": It's three of the decade's biggest artists, appearing on one of the year's most talked-about songs, promoting the hugest rap album in recent memory (Jay's The Blueprint 3, due September 11...