What do you do after spending 30 years in a Grammy-winning quartet? If you’re cellist Mark Summer, a founding (and former) member of the Turtle Island String Quartet, you create a new way to pass on what you’ve learned. From July 9 to 15, in Northern California, he’ll be offering his expertise to eight cellists (ages 21 and up) at his camp, Summer CelloBeat. They’ll be improvising in multiple styles, learning to use the cello as a percussive instrument, playing solo works, and generally learning to approach their instrument in new ways. Enrollment for few remaining spots is still open, if you’d like to spend part of your summer with Summer.