Bay seniors contemplating the leap to art making might consider stopping by the 21st Annual Clay and Glass Festival this weekend in Palo Alto. It runs Saturday and Sunday from 9-5. Prepare to be overwhelmed. It is the largest show of it kind, featuring work from both on and off the wheel, blown glass, glass beads and a whole range of remarkable creations that blur the line between and art and craft. Lessons. Demonstrations. Free.