A great milkshake requires timetime to make, and time to consume. In fact, you might have to hop into the DeLorean and go back to the 1950s, the decade Cafe Manhattan lovingly evokes, to have enough time to finish one of the diner's shakes. You can choose among only a few flavors, but do you really need anything more than the classic chocolate, vanilla or strawberry? At any rate, the thick shake in your glass, topped with whipped cream and a maraschino cherry, is more than enough to satisfy the sweetest sweet tooth. But on the side Cafe Manhattan gives you the old-fashioned tin cup filled with two or three milkshakes' worth extra. OK, maybe we exaggerate. It's certainly enough to tip a little on the ground for your lactose-intolerant homies. Or you can keep it all for yourself and nurse it while you wait for the years to catch up to 2006. By then you'll be ready for another shake.