To fully get this joke you should really read Tuesdays comic. I try not to make too many strips dependent on the previous ones for humour but I couldn't really use this joke any other way. I guess sometimes it will be unavoidable to allow a few running gags from being used.
If you are wondering who that nerdy lookin' guy in the first panel is (the one on the right smart ass) then I will tell you. Actually even if you don't care (which I am guessing is actually the majority) I am going to tell you anyways. That character is from a strip that I was making for a local zine. The comic is called 'Indie Cred' and is about a few indie nerds and the wacky indie scene they are involved in. The zine has actually not been printed yet but after it has I will try to put some of these comics up in the bonus stuff section here.