Throwing some random suggestions out here:
Thirding Pratchett, though he often has tooth beneath the amusing veneer. (If there are topics you don't want to go near, in other words, pick your title carefully.)
Carl Hiaasen writes some fun stuff.
If you just want fun, try Matt Youngmark's Choose-o-matic books, which are fun CYOA-type adventures - I howled through the many paths of his Time Travel Dinosaur.
Jim C. Hines's Jig the Dragonslayer trilogy (first book: Goblin Quest) is a fun send-up of fantasy tropes, starring a cowardly goblin forced to act as guide to a pack of pompous adventurers.
Have you tried Scott Meyer's Off to Be the Wizard? A modern programmer stumbles across the data file that controls reality, and winds up hiding out in medieval England playing wizard alongside other programmers who found the same file and messed up with their new powers. It reads like Douglas Adams Lite, and you don't need to be a computer geek to find it amusing.
Eoin Colfer's books are often fun, too, particularly his Artemis Fowl series. I also liked The Wish List, about a teenage ghost helping an elderly man fulfill his bucket list.
Brandon Sanderson's Alcatraz Versus the Evil Librarians, first in a series, an absolute kick to read, poking fun at modern YA fantasy tropes. An orphan boy with an extraordinary talent for breaking things learns that an evil consortium of librarians has been suppressing the truth about the world - for instance, there are a few continents that have been conveniently omitted from maps, dinosaurs are still alive (and far less impressive than advertised), and forces akin to magic are very much real. (Written first-person, though, IIRC, if that POV's a dealbreaker.)
I also rather enjoyed Elizabeth Kay's The Divide, about a modern boy with a heart condition who manages to fall into a world where magic is real and humans are myths. Somewhat silly trappings, but a solid storyline underneath, and a reasonably fast read.
For a lighter-toned historical, Audrey Couloumbis's The Misadventures of Maude March sends two orphaned girls across the Western frontier and into trouble, guided by the younger sister's obsession with dimer adventure rags. (Also first-person POV, though.)
L. A. Meyer's Bloody Jack series follow an 18th-century London schoolgirl who escapes death on London's streets by posing as a ship's boy... the beginning of a life of grand adventure. (Also first-person POV, but fast-paced and never dull.)
If you're exceptionally bored, click through the link in my signature, though I don't usually bother reporting the POV in a book unless something about it really stands out. (Just read the Descriptions if you don't want my opinions - I try to keep the first bits as neutral and spoiler-free as I can.)