I bought one about 10 years ago or so. It's black and clamps onto my sewing table...large enough for a big coffee mug as well. Got it from a scrapbooking shop. It's called a "Side Kick Drink Holder". Got it from Creative Memories...
www.creativememories.com
I have since bought 4 more and given to quilter friends....even got one for DH for his wood shop. Nice gifts!