Descriptions like Apollo being cursed with "a case of acne that would not respond to over-the-counter medicine" or random facts like the 3 Mile Island disaster being caused by an epic chainsaw fight between Hephaestus and Ares, caused by an insult to Ares bell-bottom jeans, or even phrases like "battle ukelele" are brilliantly delightful. I find myself not paying much attention to the plot because I just want to swim in the wonderful stream of words and phrases.
The other wonderful part of Riordan's writing is his inclusion of very obscure mythological characters, and the way that he manages to work their mythological story into his own. There is a glossary of characters and words at the back of the book that is very helpful, but I always feel like I need to have a copy of Edith Hamilton next to me so that I can refresh my memory of some of the stories. I hope that younger readers will be similarly inclined.
When The Lightning Thief came out in 2005, I (as a former Latin teacher) was thrilled just to have ONE middle grade book about mythology. Now there are multiple series by Mr. Riordan, as well as books by Anne Ursu, K.L. Armstrong, Zoe Marriott and many other authors, covering the mythology of different cultures. Not only that, put Riordan has been given a Disney-Hyperion imprint, Rick Riordan Presents, that will showcase adventures that include the folklore of different cultures.
Give Riordan books to anyone who loves mythology, action, or just a really good, well-turned phrase!