I'll second the "deschooling" suggestion. Conventional wisdom is a month for every year in public school, though I didn't find that was strictly necessary. Two or three months of "education lite" worked for us: nature programs, lots of field trips, and lots of time just chilling out and talking.
Our big hurdle was reading. The school had killed any desire to read by making all sorts of rules and regulations and assignments to surround it. My response was to go to the library regularly, and let them choose the books. They got to stay up an extra half hour to an hour at night as long as they were in bed, reading. And we kept a list of what books they'd read, with a one sentence description and a 1-5 star rating, for their portfolios.
A couple of months in we started more in-depth literature analysis, but the time off just to read for pleasure was invaluable.
