SAN MARCOS — The city of San Marcos is offering art classes for adults at the San Marcos Senior Center, 111 Richmar Ave. Classes meet from 9 a.m. to noon once per week for eight weeks, but registration is ongoing. Watercolor classes for beginning and intermediate students begin Aug. 20. Painting classes (all media) for all student levels begin Aug. 23. Ceramic classes begin Aug. 25. atercolor and painting classes are $40 for eight weeks, and the ceramics class is $60 for eight weeks. Call (760) 744-5535 to register or for more information.