The Mars Lander dug a sample from about 7 inches deep, the deepest yet, in the "Stone Soup" trench [right, credit NASA/JPL-CalTech, UA, Texas A&M] between two polygonal blocks, in hopes of finding something new. The thinking is that a variety of materials may have collected in the gap between the polygons.
The sample will go into the Lander wet chemistry lab.
August 26 marks the end of the main 90-day mission for the Lander, but NASA previously extended it for another 30 days based on its successes so far.