A game of what sport is played annually by congressional members?

Since 1909 the Congressional Baseball Game has been an annual bipartisan event beloved by all and enjoyed by thousands. Members of the United States Congress from each party solidify friendships off the floor and on the field. Over the last century, the Congressional Baseball Game’s popularity has contributed to its evolution into a foundation called Congressional Sports for Charity that supports worthy and effective Washington, DC area charities.

Source: The Congressional Baseball Game for Charity