I went to a taping last summer. I was the only standby person admitted and ended up standing with the crew since they were out of seats.
The taping I attended was fantastic. Colbert interviewed Robert Wexler, the democratic congressmen from florida who was uncontested in the upcoming election. Colbert got him to say some things that would otherwise have caused him to lose the election. "I enjoy the company of prostitutes for the following reasons... because it's a fun thing to do, much like cocaine."