Sunday, January 6, 2013 at 11:52 AM 
The president and first lady headed back to Washington, D.C. from Honolulu, Hawaii last night. While boarding Air Force One, Mrs. O wore a Merona arrow print dress from Target, previously seen here and here, paired with a cropped black cardigan and sandals. Hope everyone is having a wonderful weekend!
Update: The first lady wears the Flare sandal from the Fitflop cruise collection, available here.
Thursday, July 21, 2011 at 8:11 PM 
Photos by Jason Hirschfeld, Gerry Broome / AP Images; Elaine Sanchez / DOD Photo
The First Lady had a full Thursday, taping an appearance for Extreme Makeover: Home Edition in Fayetteville, North Carolina (where, speaking of extreme, Mrs. O had to endure stifling East Coast heat), followed by a visit to Oceana Naval Air Station in Virginia Beach, Virginia.
The Extreme Makeover: Home Edition episode focuses on a North Carolina community resource center for homeless female veterans, which will be redesigned and expanded with a new greenhouse and children’s playhouse. The episode is scheduled to air in October. The First Lady's TV appearance, as well as her stop in Virginia Beach, are part of her Joining Forces initiative with Jill Biden to support military service members and their families.
Style wise, Mrs. O stayed cool with a pair of summer dresses belted at the waist. For her TV appearance, the First Lady chose a vibrant blue and green Chris Benz Nelda dress from Resort 201, seen here, accessorized with a jeweled bee belt from House of Lavande. For the stop at Oceana Naval Air Station, Mrs. O turned to a trustworthy staple, a Merona for Target dress, paired with a Sacai belt, first seen in August 2009, here.
Some will remember that Malia Obama wore a Chris Benz dress this January, seen here. To my knowledge, this is the first occasion that the First Lady has done the same. Chris Benz is a young Parsons alum, who cut his teeth as a designer of dresses and special occasion for J.Crew before venturing out with his own eponymous label in 2007.
Chris Benz, House of Lavande, Merona, Sacai, Target Monday, August 17, 2009 at 10:46 AM 
Photo by Mandel Ngan / Getty Images
The Os made several stops out west this weekend as part of a working vacation for the president. Saturday brought a visit to Old Faithful Geyser at Yellowstone National Park in Wyoming. Mrs. O wore an ensemble quite similar to that sported in Paris, reintroducing her Rick Owen Lillies vest.
Photo by Mandel Ngan / Getty Images
Landing in Arizona, Mrs. O debuted a new summer dress, paired with a Sacai belt. We have an idea about the dress, but want to confirm details first...
UPDATE: Thanks to those who contributed fabulous tips in the comments section. We have confirmed that Mrs. O's dress is in fact Merona from Target. It is from a past collection and no longer in stores. Another major moment for democratic fashion - hooray!
Merona, Rick Owens, Sacai, Target