he New York-based chain of falafel shops has opened its first location in Philadelphia, on 18th Street. Despite the presence of Mama’s Vegetarian, Falafel Bar and a couple of top-notch falafel carts within a couple blocks, falafel is still a bit alien to the office-tower denizens who inspect Crisp’s free samples suspiciously. The falafel itself is fresh and flavorful, made continuously just steps from the front counter. But Crisp tries to entice blushing falafel virgins with its strange French, Mexican and Mediterranean variations on the classic pita sandwich. Of the fusion offerings, it’s the Athenian that shines most, tzatziki sauce, feta and kalamata olives being natural accompaniments to falafel. Still, the most innovative part of Crisp’s model is the packaging that breaks down to serve as a pita stand, so no tricky falafel balls escape while you’re looking away.