There are some wonderful jokes about Congress - many told by Senators and Congressmen themselves. One Senator known for his encyclopedic knowledge of such jokes is Bob Dole, Presidential Candidate for the Republican Party in 1996 - who served in the Senate from 1969-96 was was Majority and Minority Leader.
He has collected many of those jokes in his book "Great Political Wit" (Subtitle: 'Laughing (Almost) All the Way to the White House")
Some of my favourites -
Eugene McCarthy "Being in politics is like being a football coach. You have to be smart enough to understand the game....and dumb enough to think it's important"
Adlai Stevenson "An independent is someone who wants to take the politics out of politics"