The "Which Came First...?" calzone: roasted chicken, applewood-smoked bacon, jalapeños, egg, onion and mozzarella; served with a salsa verde on the side.
Sauce on the Side (903 Pine Street; 314-241-5667) does one thing and does it very well: calzones. My review of Sauce on the Side is now available online.
Also now online is Jennifer Silverberg's slideshow of Sauce on the Side.