How do I ask instructors for more challenging and/or interesting homework? This question is prompted mostly due to a Numerical Methods and Computer Programming In MATLAB course I took this summer (textbook). To summarize the course it's basically methods for solving linear, nonlinear, and differential equations and systems of those equations, and learning how to program the respective algorithms in MATLAB. 

I'm a fast learner for most topics. I already have programming experience, so that half of the class was no challenge. The mathematical concepts I grasped quickly, and as a result most of the lectures were too slow for me.  This isn't anything new for me, I often have this issue. 

The bulk of the homework problems given were standard book problems and had no real significance or relation to the application of these methods. There were one or two problems that were applied and those were great, but to be honest I have a problem doing homework and have had it for around 20 years now (since grade school). I understand the importance of it, it's rarely (if ever) difficult for me, but it bores me and I have no motivation to do it. It doesn't help that now I work full time with a wife and 1.5 children, so there is a small window in which I even have to fit this homework.

A couple of weeks into the course I thought perhaps if the homework was more interesting somehow (puzzle-like, application problems (aka story problems), etc) then that would be better for me, but I didn't know how to approach the professor about this. Long story short the bulk of the grading is homework and I'm not doing as well as I could be. It's likely too late for this class, but how would I approach this in the future? It'd be torture to have to continue down this road.
Why not just ask?  Maybe this seems naive but if you approach the professor and say, honestly, you don't feel you are doing as well as you could or even should be, they would be willing to discuss that; a student taking an interest in their learning is a valuable thing.  You can state your desire for creative questions, and ask if the professor has any recommendations for outside material, or has some of their own.  I can't imagine any professor being anything but delighted at the prospect of a student being self-aware of their performance hurdles and seeking more advanced knowledge in the professor's field.