Curiosity skipped arm testing on Sol 31 (Sept. 6) after controllers held back on new commanding due to a caution about a temperature reading on the arm. The issue was resolved later in the day, so the planned activities have shifted to Sol 32 (Sept. 7). These include a checkout of the tool turret at the end of the arm and a test using vibration of the sample processing device on the arm.
The downlink during Sol 31 returned a Navigation Camera image of the turret taken during testing on Sol 30. It can be seen among the raw images from the rover at: http://1.usa.gov/NPGnIp .
Curiosity continues to work in good health. Sol 31, in Mars local mean solar time at Gale Crater, ended at 3:56 a.m. Sept. 7, PDT.