I ran across a neat book a little while ago that was designed as an introduction to numerical calculation in the context of gravitational science, starting with a 2 body system and going through many body. It has a good introduction to things like different order integrators, energy conservation, and stability. They decided to use Ruby for the book as a simpler introduction to programming than traditional languages. I think the intention is to include this in a classroom setting, so it will be interesting to see how that works out.
From my personal experience with this type of class (numerical programming, not gravitation) I really think it will help, because so much overhead of the class is dedicated to how to get the compiler to work and all of the wrangling with things that aren’t really important. There is a point where you need to introduce some C code for performance reasons (which is also discussed in one of the chapters), but the nice thing about Ruby is that you can do so much of the prototyping and “learning” in Ruby, then replace a very small amount of code and get tremendous performance gains. It would be very easy for the C part to be provided to a class once students have proven that they can implement the algorithm in Ruby.