As you're scouring Valencia Street for unique Christmas gifts that don't scream "Amazon.com FREE Super Saver Shipping," don't forget to make your way down to the ripe little section of 16th Street at Mission. That's where the Lab sits, and for the past 10 years it's hosted a big small-format art sale every December. For eight days, Post-Postcard 11 turns the space into a "bazaar-like bargain-hunter's paradise," which is exactly the sort of thing you like to hear when it comes to local art. Dozens of artists contribute hundreds of pieces, priced at $1-$30, with the only stipulation being that each artists collection fits entirely into a 6-by-11-inch box. Previous sales included the likes of Tracey Snelling, Matt Furie, and Veronica de Jesus, so we suggest treating Post-Postcard like your own little Black Friday and getting there early.