What makes the Greek myths in the Lightning Thief appeal to modern-day kids?
Are you kidding? What modern-day kid isn't enthralled with magic, magical creatures, flying without planes, abnormal strength, and other equally cool stuff?!
Percy is just like most kids in my class. He is restless, diagnosed with ADD, and his mind wanders profusely. He isn't interested in school, doesn't like reading, but is intrigued by the stories of the Greek gods. When his teacher turns into some magical bird with huge wings and tries to attack him, he is really focused.
He is intrigued by the stories of gods having children with mortal women, and well he should be since he is actually the son of Poseidon. Of course, he's never met his real father, but he does have many of his attributes, including, but not limited to, his love of water.
There is also the story of the Sirens and their ability to lure people in and trap them for years at a time with their lotus potions. Percy and his friends visit this place and are trapped for a short while during their search for Zeus' lost lightning bolt. However, once they realize they should stop eating the lotus that flows freely at this outrageous party, they are once again clear-headed and able to focus on the task at hand.
Percy is also intrigued by the other children of gods and goddesses that he meets and trains with at the camp. There, he discovers that he does indeed have hidden powers and that he is much stronger than he ever imagined. The coolest thing he can do is heal himself and others using water...a clear clue as to his parentage. What modern boy wouldn't want to be able to do that?
These stories are timeless and universal. It's obvious from all the TV shows about heros and people with special powers that this sort of thing continues to amaze and captivate people of all ages.
The main character, Percy, is what what most kids can relate to. The Greek myths are real, but brought to modern time, so kids can relate to the story.
Last of all, the story is about magic, magical creatures, arcane, mythical and mystical gods, which would definitely make a kid interested.