Yes, Penny has a lot of money tied up in promiscuity futures.

Sheldon

Sheldon's mom: ... there's no harm in trying something new.
Sheldon: There's a lot of harm in trying something new. That's why we test out drugs and cosmetics on bunny rabbits.

Frankly, Mom, I'm encouraged to see how advanced your group has become -- willing to sail into the ocean without fear of falling off the edge.

Sheldon

It's all themed. There's Jonah and the Whale Watching. All-you-can-eat Last Supper Buffet. And my personal favorite, Gunning with God.

Sheldon's mom

Sheldon [reading inscription]: "To Sheldon, sorry this took so long. Your friend, Wil Wheaton."
Wil: It's my last one and I want you to have it.
Sheldon: Look everyone, Wil Wheaton is my friend.

And you're going to have to choke back a hot sob of regret and humiliation as you mumble "I was, but I chose to go to a party thrown by the one kid from 'Stand by Me' that no one remembers."

Sheldon

Leonard: I'm going to a party. I'm not turning R2-D2 and C3PO over to the Empire!
Sheldon: Not yet.

... it was cooler for him to be the lower-left corner on Hollywood Squares.

Sheldon

Sheldon: This will just take a moment, it's on a five and a quarter inch floppy.
Amy: A floppy disk?
Sheldon: Well, I started the list when I was nine.

Penny: Wil Wheaton is Sheldon's mortal enemy.
Amy: Mortal enemy?
Penny: Mm-hmm.
Amy: Sheldon, I know you are a bit of a left-handed monkey wrench but... you really have a mortal enemy?
Sheldon: In fact, I have 61 of them.

Oh, boo-hoo, you're not going to space!

Bernadette

Howard: You know, there's a saying we have at NASA. What makes the right stuff so right is that it always comes home.
Bernadette: Stop talking, Howard.

The Big Bang Theory Season 5 Quotes

You can't blame yourself. When your prefrontal cortex fails to make you happy promiscuity rewards you with the needed flood of dopamine. We, neurobiologists, refer to this as the skank reflex.

Amy

I feel like two totally different people. Dr. Jekyyl and Mrs. Whore.

Penny