The Artemis Fowl series by Eoin (pronounced Owen) Colfer is a series that, although marketed to kids, is (like Sesame Street) extremely enjoyable for adults. A fantasy/tech series which centers on Artemis Fowl (who complains of having a girl's name - he's obviously never heard of Artemis Entreri) a child who takes over the criminal enterprises of his father, Artemis Sr. Young Artemis is always planning many moves ahead, to the extent that he nearly never needs to think on the fly, but when the need arises, he is more than capable of such mental feats. In the first installment, Artemis conspires to capture a Leprecaun and ransom it for gold. Actually, Leprecaun is a misnomer, as it is actually a bastardized form of LEP-recon, LEP standing for Lower Elements Police, the Lower Elements being fairies and mythical beings of all sorts who reside many miles underground. Quite a good series, definitely worth the read, reads extremely fast, and evolves with the characters.
Also available as some of the finest unabridged recordings I've ever heard.
As an aside, it was Eoin Colfer who was chosen by the estate of Douglas Adams to write the conclusion to the Hitchhiker's Guide series: And Another Thing. However, to my mind he goes way overboard on guide entries in that book, to the extent that the actual narrative is extremely slight. Not a problem with the latter series, though.