You're probably thinking, "the comic book store, on a Thursday? Why I've fallen down the rabbit hole and into a land of madness." What you have failed to take into account, Penny, is that this is "Anything Can Happen Thursday"

Sheldon

Sheldon: More wrong? Wrong is an absolute state and not subject to degradation
Stuart: It's a little wrong to say to say a tomato is a vegetable, it's very wrong to say it's a suspension bridge

Wolowitz: First we let the lawyers and the jock thin the heard, then we go after the weak, the old and the lame
Leonard: That's your system?
Wolowitz: Yeah and if you spot a girl with a seeing eye dog, she's mine

Wolowitz: Okay! Let me just go inside and slip off my underwear.
Leonard: Why?
Wolowitz: Well if I get lucky, I certainly don't want to be caught in my Aquaman briefs.

Leonard: I just don't get what she sees in Stuart, we're practically the same guy
Sheldon: ...Stuart is taller, artistic, self employed, and most importantly, gets 45% off comic books

Penny [to comic book store owner]: What would you recommend as a gift for a 13 year old boy?
Stuart: A thirteen year old girl

Penny [at comic book store]: Everyone's staring at me!
Leonard: Don't worry, they're more scared of you than you are of them
Penny: Unlikely

Raj: The Wolowitz coefficient?
Wolowitz: Neediness times dress size squared

Leonard: But we all agreed the third Thursday of every month will be "Anything Can Happen Thursday"
Sheldon: Apparently the news didn't reach my digestive system, which when startled has it's own version of "Anything Can Happen Thursday"

Wolowitz: According to Alicia's Facebook page, she's hooking up with one of the producers on CSI.
Penny: Dead whore on TV, live one in real life.

Listen to that! "Stomp, stomp, stomp." It's Wolowitz and his stacked heels that fool no one.

Sheldon

Sheldon [looking for musical instrument in new neighbor's boxes]: Do those sound like castanets to you?
Leonard: The box says "kitchen."
Sheldon: So? Do cocaine smugglers write "cocaine" on the box?

The Big Bang Theory Season 2 Quotes

Sheldon: I'm a physicist. I have a working knowledge of the entire universe and everything it contains
Penny: Who's Radiohead?
Sheldon [after twitching for a minute]: I have a working knowledge of the important things

Sheldon: More wrong? Wrong is an absolute state and not subject to degradation
Stuart: It's a little wrong to say to say a tomato is a vegetable, it's very wrong to say it's a suspension bridge