When Hallmark's artists, graphic designers and copywriters aren't thinking of clever cards for Valentine's Day or Eid al-Fitr (the end of Ramadan), they're often working on their own projects. They take that extracurricular work to market: Hallmarket, located at Hallmark Square at Crown Center (2501 McGee Trafficway). About 100 photographers, sculptors, designers and photo stylists display and sell their pieces 10 a.m.–5 p.m. It's cash or check only, and admission is free.