The X-37 B returned to Earth, Dec.3rd/10.
I have covered the X-37B previously here and here.
So if you are unfamiliar with the topic you may wish to read those first.
The X-37B was reported to have launched late April 2010.
So it was in flight for better then 7 months. According to the first article linked , the spacecraft spent 22o days in orbit. 220 days. Quite long.
The U.S. Air Force's mysterious X-37B robot space plane returned to Earth today (Dec. 3) with a successful landing at Vandenberg Air Force Base in California before sunrise. Air Force officials hailed the unmanned space plane's successful landing, though its mission remains shrouded in secrecy because of its classified nature.
The X-37B began its life in 1999 as a NASA project, then transferred to the Pentagon's DARPA office in 2004. The Air Force took over in 2006. This mission launched on April 22, 2010. The flight's purpose and cost are classified.
Photo from Space.com, with many more available there. Click first link.