Break out those holiday sweaters and woolen mittens, folks: Union Square's first ice rink opens this morning at 10 a.m. and will stay open through January 4. Will it boost the local shopping? Not if everyone's spending their cash on skates and hot chocolates. Admission is a cool $8, and yes, the rink is available for private parties. No word on whether there will be economic stimulus specials. [via Rincon Hill]For more stories from Curbed SF, go to sf.curbed.com.