Now, if Glenn Beck testified before Congress it would likely be a melodramatic event laden with his signature conspiracy theories and trademark chalkboard. People would laugh, but not because Beck is a comedian, but because his theories are so odd.
However, Colbert evoked roaring laughter from viewers of CSPAN3 as he testified over illegal immigration and migrant workers at Congress. You can see a video of Stephen Colbert here.
With Colbert's recent visit to Capital Hill, and the constant jabbering about the dual rallies there's a distinct possibility that the rally could be even bigger than Beck's.