Frozen yogurt goes late-night at this self-serve River North spot, where you can fill up your own 16-ounce paper cup until 3 a.m. Choose from 14 flavors; vanilla, chocolate and red velvet cake are always on hand, while seasonal selections such as pumpkin, blackberry and pomegranate-raspberry also rotate into the mix, all for $0.45 an ounce. Froyo's 40-plus toppings include mango and other fresh fruits, candy and organic nuts. Wondering what flavors are on tap for the day? Just check the TV screens for menu details before you make your way to the stainless steel counter.