For adult education, one of the first places that pops into my head is
The Learning Annex, which is low cost, short term classes for adults.
The people who teach those courses, really have no special skills at all other than they percieve themselves to be an expert in the field they are teaching. YOu could even design your own course and submit it to them for something for you to teach.
There are also online courses that you could look into teaching.- and even some offered thru community colleges (Years back, I had sumitted my resume to a community college in Queens, NY, to teach a computer course, and was offered a position site unseen, no interview needed either. (I declined) Adult Ed programs you could do without any real extensive training.
There are also places like
Berlitz which are language centers, where business folks would go to get instruction on a foreign language.