Driving is so last year. Jump on the eco-bandwagon and embrace the beauty of zero-emission transportation by choosing two wheels instead of four. Popular with cool kids in bike-friendly countries like Denmark and Japan, folding bikes are undeniably hip and supremely convenient. Case in point, the nifty Gotham model from Citizen Bike. With a utilitarian motto, "Folding bikes for going and being human," and proletariat pricing, the Florida-based company's rides are a natural choice. Super portable, they appeal to everyone from creative commuters [they're subway friendly] to RV-living retirees. Popular with boaters and urban dwellers with little storage space, the futuristic bike complements iPhone-wielding mavens with its sleek design and practical features. Like metal origami, the frame folds to a compact suitcase size, ideal for storing in the office or closet. Made of non-rusting lightwight aluminum, it features 20-inch wheels and a six-speed shifter for life's ups and downs, and is perfect for running quick errands on Lincoln Road or to take along on jaunts to the Bahamas. For those who like a little celebrity with their green, look out for the bikes under the tushies of Jude Law and Forest Whitaker, as it's featured in their forthcoming film Reposession Mambo, a futuristic sci-fi thriller that's set for release next year.