[ghubbard]

If you want to teach without leaving the house or standing in front of a group of people, try http://exercism.io/ (Open Source and free).

Solve simple coding problems, review the submissions of others and help them become better coders. Trying to clearly explain concepts to others is the best way to make sure you really know them yourself.

This is also something that you can do for 10-15 min every day, which will add up over time. Ask for feedback on your own solutions and find out ways others think you could improve things.