You can think of a million reasons not to go to the gym today. (Too tired. Too cranky. Dog ate my sports bra.) But your best excuse? It’s boring. Sure you love the results, but the process ain’t exactly an exercise in freewheeling creativity. Maybe you’re better suited for the Craft Gym, which is run out of a Potrero Hill elementary school and offers evening classes in knitting, tilemaking, linocutting, screen printing, ceramics, candlemaking, and myriad other creative pursuits. No equipment or materials needed — just show up ready to get crafty. They do one-on-one lessons (for the needier craftster), finishing services (for procrastinators), and private parties (perfect for bridal showers). Craft Gym also hosts charity craft-ins, like the upcoming Chemo Caps event: Spend the evening with like-minded folks making and decorating caps for Bay Area cancer patients. You may not burn a lot of calories or leave with rock-hard abs. But you’ll definitely see results. Craft Gym, 1452 Bush Street, between Van Ness and Polk Streets (415-702-5700 or craftgym.com).