Unfortunately I won't be making it to the rally, I have a prior engagement to view an ultrasound for my recently discovered unborn child. It would be fun though, I saw Colbert live at the Olympics and had a blast.
To address a few things that have been said so far though, I think it's less the tea party ideals that are being made fun of and more some specific things that have happened over the past few years that come off as less than the tea party ideals. Consider that one of the signs Jon Stewart suggested be made for the rally is "I disagree with you but I'm pretty sure you're not Hitler" and I think you have the heart of the mater here. To be honest I find the extremely one dimensional scale of Liberal vs Conservative an entirely inadequate and often flat out incorrect tool for measuring peoples views. And for the record I'm a registered independent.