Burlington artist Sage Tucker-Ketcham is definitely calling it quits, and giving it a date: December 1. That's when her 12 North Street gallery, Studio STK, will close its door for good. "I hope to continue to be a part of Burlington's art community," she says, "but I need to focus on my art." Currently a graduate student in painting, Tucker-Ketcham hopes she'll be able to "do it again someday - with more seed money and a better business plan." Meanwhile, check out a closing open house this Saturday from noon to 4 p.m., "with clear-out prices and more." And, by the way, she says Secret Movie Night "is still on for now" . . . Also at Studio STK this Friday, November 9, at 7 p.m., Craig Mitchell puts on his one-man show, Do Unto Others - a "soul-stirring mixture of song, laughter and tears." Sounds like an appropriate, if inadvertent, send-off for the venue . . .