What are some side jobs with which a mathematician in a postdoc or non-tenure-track position can make ends meet?
Universities (especially if they're large R1 universities, almost certainly if they're in top 10) usually ask its department members whether they are willing to teach a calculus/lower-level math courses in the summer for extra pay. These are often accelerated and they are over in a couple of months. Teaching one class, in my estimate, should earn you an extra 5-10k, depending on your institution. You can easily pick up two of these classes over the summer. If there is more than one university in your area, you could also try teaching at the other universities.

You could also tutor students. This is admittedly a little awkward when you are a faculty member, but as long as you are not teaching them, there shouldn't be any problems. This works especially well in an affluent area; I'm told that some people, given good credentials, can support themselves completely on tutoring students.

Sometimes, websites dedicated to math education, such as Art of Problem Solving, hires online graders. The flexibility of the job means that you can pick it up on top of being a postdoc.

Lastly, remember that you're on a 9-month salary contract. This means that you could be an intern at some large company using your statistics/programming skills during the other three months, and earn a huge paycheck. 

These are not really "odd jobs", but probably the easiest to get given your situations. Of course, you should keep in mind that these will take away from your research time, which might make finding a tenure-track job more difficult (I totally sympathize with you; the system that we have is far from perfect, and it puts so many people in your position. But this is the reality and you should be aware of it when you're contemplating taking up another job on top of your postdoc position, which is already more than a full-time job).