Nico Di Angelo, Zoe Nightshade, Thalia Grace, and Atlas, the monstrous army general, were all introduced in the third book of Percy Jackson and the Olympians, which was Percy Jackson and the Titan's Curse.  Who doesn't love this fan favorite book with funny and exciting snippets? I certainly do! 

1. In I Have a Dam Problem : "Let us find the dam snack bar," Zoe said. "We should eat while we can."

Grover cracked a smile. "The dam snack bar?"

Zoe blinked. "Yes. What is funny?"

"Nothing," Grover said, trying to keep a straight face. "I could use some dam french fries."

Even Thalia smiled at that. "And I need to use the dam restroom."
...
I started cracking up, and Thalia and Grover joined in, while Zoe just looked at me. "I do not understand."

"I want to use the dam water fountain," Grover said.

"And..." Thalia tried to catch her breath. "I want to buy a dam t-shirt."

2. In Thalia Torches New England: "He cleared his throat and held up one hand dramatically.

"Green grass breaks through snow.

Artemis pleads for my help.

I am so cool."

He grinned at us, waiting for applause.

"That last line was four syllables." Artemis said.

Apollo frowned. "Was it?"

"Yes. What about I am so bigheaded?"

"No, no, that's six syllable, hhhm." He started muttering to himself.

Zoe Nightshade turned to us. "Lord Apollo has been going through this haiku phase ever since he visited Japan. Tis not as bad as the time he visited Limerick. If I'd had to hear one more poem that started with, There once was a godess from Sparta-"

"I've got it!" Apollo announced. "I am so awesome. That's five syllables!" He bowed, looking very pleased with himself.

3.  In An Old Dead Friend Comes to Visit: "Argh!" Thalia pushed me, and a shock went through my body that blew me backward ten feet into the water. Some of the campers gasped. A couple of the Hunters stifled laughs.

"Sorry!" Thalia said, turning pale. "I didn't mean to—"

Anger roared in my ears. A wave erupted from the creek, blasting into Thalia's face and dousing her from head to toe.

 stood up. "Yeah," I growled. "I didn't mean to, either."

Thalia was breathing heavily.

"Enough!" Chiron ordered.
But Thalia held out her spear. "You want some, Seaweed Brain?"

Somehow, it was okay when Annabeth called me that — at least, I'd gotten used to it — but hearing it from Thalia was not cool.

"Bring it on, Pinecone Face!"

4. In I Place An Underwater Phone Call:  "And, whoa!" He turned to Mr.D. "Your the wine dude? No way!"

Mr.D turned hi eyes away from me and gave Nico a look of loathing. "The wine dude?"

"Dionysus, right? Oh, wow! I've got your figurine!"

"My figurine."

"In my game, Mythomagic. And holofoil card, too! And even though you've only got like five hundred attack points and everybody thinks your the lamest god card, I totally think your powers are sweet!"

"Ah." Mr.D seemed truly perplexed, which probably saved my life. "Well, that's...gratifying."

5. In I Go Snowboarding With A Pig: "I looked at Thalia. "You're afraid of heights."

Now that we were safely down the mountain, her eyes had their usual angry look. "Don't be stupid."

That explains why you freaked out on Apollo's bus. Why you didn't want to talk about it."

She took a deep breath. Then she brushed the pine needles out of her hair. "If you tell anyone, I swear—"

No, no," I said. "That's cool. It's just... the daughter of Zeus, the Lord of the Sky, afraid of heights?"

What was your favorite Titan's Curse moment? I really can't choose! It's just such a good book!