The Percy Jackson series—they have been after me to catch up on these for ages.
The Mysterious Benedict Society and the Perilous Journey (book #2 in the series—you know how much I loved the first one).
The Ruby Key by Holly Lisle (and I think this was sent to me as a Library Thing review copy, so I really need to get on the stick).
Countless others, but those are the ones placed enticingly on the shelf next to my bed at the moment.
Of Ferns and Firelings
Martha and Charlotte Books Available
Snufkin gets it