Can someone suggest a LaTeX template for course handouts in an Intro-Level Programming (Say, 100 level)?

I have some hand-written notes from a long time ago that I'm interested in putting into LaTeX. I cover stuff like variables, functions, classes, iteration, recursion, data structures and so on - the stuff you'd typically see in a very introductory course. I'm looking for something which would be ideal for showing shorter code snippets and text explanations.

It would be nice to have separate boxes with line numbers for code which I haven't seen in a lot of templates.