Most liberal Senators:
Sherrod Brown (D-Ohio)
Roland Burris (D-Illinois)
Ben Cardin (D-Maryland)
Jack Reed (D-Rhode Island)
Sheldon Whitehouse (D-Rhode Island)
Most conservative Senators:
James Inhofe (R-Oklahoma)
Jim DeMint (R-South Carolina)
Jim Bunning (R-Kentucky)
Tom Coburn (R-Oklahoma)
Jim Risch (R-Idaho)
Most liberal House members:
Rush Holt (D-New Jersey)
Gwen Moore (D-Wisconsin)
John Olver (D-Massachusetts)
Linda Sanchez (D-California)
Jan Schakowsky (D-Illinois)
Most conservative House members:
Trent Franks (R-Arizona)
Doug Lamborn (R-Colorado)
Randy Neugebauer (R-Texas)
Pete Olson (R-Texas)
John Shadegg (R-Arizona)
And right in the middle:
Sen. Mark Pryor (D-Arkansas)
Sen. Byron Dorgan (D-North Dakota)
Rep. Michael Arcuri (D-New York)
The Most Conservative and Most Liberal Members of Congress - Peter Roff (usnews.com)