Parody for charity, with help from indie-rock gods.(Preview)

Byline: JESSE FOX MAYSHARK New York Times

If parody can be called a form of flattery, then Bob Geldof has cause to blush.

Twenty-one years after he gathered a group of musicians for the all-star "Do They Know It's Christmas?" benefit single, a similarly sprawling group of performers is asking a snarky follow-up question: "Do They Know It's Halloween?"

The single, being released next week to benefit UNICEF, features indie-rock luminaries like Beck and the Arcade Fire, and pokes fun at what many see as the original Band Aid song's culturally patronizing attitude toward the Third World.

" `Do they know it's Christmas?' What a ridiculous question to ask someone!" Nicholas Diamonds, the Canadian musician who helped write and produce the new …