My main source of income is from teaching. My wife tutors and brings in some good cash that helps out, but I do a lot of odd jobs that bring in money also.
Besides teaching ways I've brought in cash:
Sold Starbucks cards for ca$h
Announce volleyball, basketball, softball for high school
Built a swingset
Worked for my brother while vacationing
Morning and afterschool programs
I am sure I have made an additional $5000 on top of my teacher salary just being willing to do the extras.