I teach part-time at a few tech schools and universities (because, as discussed, there's practically no chance of tenure track at this point).
Here's how they pulled their shit on me: on paper, I make about $25/hr (it depends on school a little), which if it were full time, wouldn't be a completely terrible salary. Good enough for me since the hours are a bit flexible and I enjoy teaching, and live a pretty modest life anyway.
The problem gets to be that they tell you up front that the $25/hr is paid ONLY for contact hours with students each week -- hours you are physically in class. However, you are still expected to (1) work on curriculum, (2) hold office hours, (3) answer emails from home (within 24 hours), (4) grade papers and tests.
Considering that for every hour I am in class, I probably spend a good 2 hours or so of class prep and then another hour or two grading, I estimate that I, in actuality, make roughly $12/hr at a maximum if you take my salary and divide it by the total number of hours I spend on classes. $12/hr on the higher end, if it is a class I have taught before and I have older notes to work with -- probably more like $8/hr if it is a new class that I need to spend extra time on preparing materials. It is absolutely obscene.
I made $25k or so last year teaching -- and for most of the year, teaching full time, split between a few schools (in fact there was a semester that I counted and I probably put in about 70 hrs a week because I was teaching 6 classes - more like 80 when you include the commute times all over the city to the different schools). For what? To make myself insane, to see my bank account drain, and not even do a great job for my students -- not because I don't want to (I used to have excellent student reviews!), but because I'm just too damn exhausted to even care.
I'm in the process of winding down my teaching "career" now and moving back to private jobs. I started some work on contract jobs, and am currently interviewing at a few places so I doubt I will be teaching much longer. I simply can't afford to. Which is a shame, because I honestly love teaching, I have a lot of fun working with students, and it's been my dream job -- but actually doing it has been a nightmare of no sleep, no seeing family, and tightening the budget more and more "just in case they decide they can't give me 3 classes next semester and I have no where else to go". It's a good thing the wife could supplement a bit (though her job in industry wasn't safe -- she recently had to start training some Indians, yeah, can see where that is going...). NO MORE.
My silly dream, after I get my life together in a non-academic job/salary for a couple of years, is to go back and start my own damn college (maybe not a full university, but a specialized college in my field) and compete with these asshats. Better education, lower tuition, better instructor pay. I don't know how easy it is, but man would I love to do it.