EARTH TO NYC: Shop for eco-friendly wares (from apparel to bath and beauty must-haves) from nearly 50 vendors at Grand Central Terminal's Earth Fair, while you take in free live music (including Dar Williams) and eco-minded artwork (including Andy Warhol). Fri. 12-7PM, Sat. 11AM-5PM.
WORKS FOR US: Housing Works Thrift Shops is opening a new outpost in SoHo, and they've amassed a trove of gems to lure you in -- on the hook is stuff like a $70 Marc Jacobs jacket and $500 ostrich leather couch. Also there'll be DJs, refreshments, Housing Works tees with purchase, plus the satisfaction of putting your money to a good cause. (Bonus: HW members get in an hour early.) Sat. 10AM-7PM.
MEGASALE: Is the Virgin Megastore at 14th Street fixing to close? Officials fervently deny it, but the Times Square outpost is long gone, and the Union Square store just kicked off a massive sale on pretty much everything, with discounts starting at 20 percent off. Don't ask questions, just shop. All weekend.
DO GOOD FOR $1: Buffalo Exchange, the much-loved (gently) used apparel and accessories chainlet, is slashing prices on lots of items to a single dollar each during its Save the Whales by Shopping sale. Even better, proceeds will go to the Humane Society. Sat 11AM-7PM.
A VERY GOOD YEAR: Need we remind you about the Manhattan Vintage Clothing Show at the Metropolitan Pavilion Friday and Saturday? With 2,000 fabulous pieces of eras-past fashion for you to have and to hold? Okay. Consider yourself reminded. Fri. 1-8PM, Sat. 11AM-6PM.