Tutoring is a great option. In some communities, tutors who are "real" teachers can easily make $25 an hour or much more. Tutoring for the SAT, ACT and AP courses commands especially high rates. Add the GRE, MCAT & other college-level tests to that list too.
Another idea is to publish your worksheets and lesson plans. Sell downloads or print copies. That's what my sister & I are doing... We had already spent hundreds of hours creating the content anyway.
Gotta say... As a former teacher, it really irks me that I could earn more per hour with ONE kid than with 26 at a time :-(. Teachers shouldn't have to take on more work. Teaching is much more exhausting mentally, physically and emotionally than people realize -- if you're an awesome teacher, anyway.