pypeFLOW is light weight and reusable make / flow data process library written in Python.
Most of bioinformatics analysis or general data analysis includes various steps combining data files, transforming files between different formats and calculating statistics with a variety of tools. Ian Holmes has a great summary and opinions about bioinformatics workflow at http://biowiki.org/BioinformaticsWorkflows. It is interesting that such analysis workflow is really similar to constructing software without an IDE in general. Using a "makefile" file for managing bioinformatics analysis workflow is actually great for generating reproducible and reusable analysis procedure. Combining with a proper version control tool, one will be able to manage to work with a divergent set of data and tools over a period of time for a project especially when there are complicate dependence between the data, tools and customized code for the analysis tasks.
However, using "make" and "makefile" implies all data analysis steps are done by some command line tools. If you have some customized analysis tasks, you will have to write some scripts and to make them into command line tools. In my personal experience, I find it is convenient to bypass such burden and to combine those quick and simple steps in a single scripts. The only caveat is that if an analyst does not save the results of any intermediate steps, he or she has to repeat the computation all over again for every steps from the beginning. This will waste a lot of computation cycles and personal time. Well, the solution is simple, just like the traditional software building process, one have to track the dependencies and analyze them and only reprocess those parts that are necessary to get the most up-to-date final results.