Magic items

Magic items are magical items given to demigods by their Olympian parents. Percy was given his by Chiron, not his father, but it is from the sea.

Magic Items are used by characters for a lot of stuff, they use them in Capture the Flag, fighting and other stuff.

Riptide
Percy Jackson was given Riptide by Chiron in The Lightning Thief to fight against his "math teacher" Mrs. Dodds (aka a Fury). It is made out of celestrial bronze witch will not harm mortals but will "pass through them like an illusion". It is magic in that it can not be lost, if you through it away it will apear in your pocket a few moments later.

Hermes' Gifts
As Percy is leaving on the quest in The Sea of Monsters he sees Hermes who gives him some gifts.

Vitamins
Hermes gives Percy some vitamins that counteract all magic for a time. Percy uses those to escape from being a guinea pig after being turned into one by Circe. There are different flavors, and are in the shapes of the Minotaur, a Fury, and such.

Thermos of winds
Hermes gives Percy a thermos that contains the four winds of the North, South, East, and West. The lid is also a compass. Percy lets one wind go to gain speed to catch up with Clarisse, and the rest to fall away from the center of a whirlpool.

Invisibility Yankees Cap
Annabeth has a magic Yankees baseball cap given to her by her mother Athena for her twelth birthday.

Electric spear
In his first game of capture the flag Percy was told to watch out for Clarisse's spear, he later got stabbed by it and felt electricity run through him. When he fought back he broke the spear getting Clarisse very angry. In The Last Olympian, she gets a new spear which she calls "Maimer", but everyone else calls "Lamer". It was broken when Clarisse charged a Drakkon.

Fart arrows
These arrows explode into a cloud of stinky yellow smoke when they hit something. They are used by the hunters in the game of capture the flag and Thalia calls them "Unsportsmanlike".

Sonic arrows
Sonic arrows make a screaming noise as they are shot.