I read Helen's post a few days ago and really, really, really liked the mug she got, so I googled "mug knit on with confidence" and found this site. I didn't find one with the Zimmerman quote, but I only looked through the first ten (!) pages of mugs. (Apparently they have more than 1,200 mugs about knitting or other fibery craft.)
Some of my favorites:
Other favored captions:
- "'Heirloom' is knitting code for 'The pattern is so difficult that you would consider death a relief.'" –Stephanie Perl-McPhee
- The ever-classic "Got yarn?"
- "If I am sitting, I am knitting." (This one is absolutely true for me.)
- No caption, just a Mona Lisa holding her knitting.
- "Knitter by day, rock star by night."
p.s. The Google finally led me to Etsy, where the original mug can be found. Tragically, it sold last March.