Skinny Dip offers (typically) three different flavors of yogurt at a time (regular, chocolate, mango and raspberry have all been available when I've been there). They have fresh fruit options as well as various sweets to put on top. I like going to Skinny Dip because the yogurt is low calorie and there are healthy options for toppings.
I recommend sampling the flavor of frozen yogurt before purchasing because the regular and fruit flavors tend to be rather tart (which I was not used to).
Keywords: Dessert / Ice Cream, Just you alone / As a single, Dress casual, With teens, Outdoor / Patio seating, Other place to eat, Cafe / Tea House / Coffee Shop, Good for first date, Everyone, With a group, Cheap (US$ 5 - US$ 10), With kids, "In" place / People watching, American, As a couple