Vice President Joe Biden's daughter Ashley got married last weekend to Howard Krein in Delaware. Because the Bidens are Roman Catholic and Krein is Jewish it was an interfaith wedding with both religions taking part.
As per Jewish custom, the party guests did the Horah, a traditional but exuberant dance often done at celebrations like weddings and b'nai mitzvah.
Below is the White House photo of Biden doing the Horah. Mazel Tov.