According to The Washington Post, a UPS truck traveling on Independence Avenue crashed through a concrete barrier and into the Hirshhorn Museum and Sculpture Garden at approximately 8:30 pm last night. From the article:
Outside the building, according to officials' accounts, the truck ran through the low concrete structures that serve as flower pots and provide protection. Linda St. Thomas, spokeswoman for the Smithsonian Institution, of which the circular-shaped museum is part, said the truck came about one foot into the building...The museum, described as a low cylinder perched on legs, exhibits art on the two floors above the ground level. No art was affected by the crash, officials said.
Since no art was damaged in the crash, the museum is expected to reopen today.
The Hirshhorn has plans to create a temporary inflatable structure in the courtyard twice a year, starting in May 2011, and is in the process of receiving approvals.
Update: The Washington Post has another article about the crash, this time describing why the UPS truck didn't cause more damage to the building - the concrete planters in front of the museum.