This is a mechanism for converting Chef cookbooks to Puppet classes and modules. It is intended to work with Chef recipes built largely using the DSL without resorting much to other Ruby code. It is pretty functional now and generates Puppet classes with mostly correct syntax. The output is a complete Puppet module directory structure. You will definitely need to hand edit the resulting Puppet code, but probably not much.
The script sets up a dummy environment in which the Chef DSL can be evaluated. Rather than doing anything, the evaluated code simply prints out Puppet(ish) formatted classes that can then be edited by hand to make them correct. The goal is that you will need to do a minimal amount of work on the output to make it clean, but since Chef lets you use all the power of Ruby it's too large a task to capture all possible intentions.
Output is all into a directory structure than can be copied to the Puppet modules directory, including the original files and templates. Inside of templates, an attempt is made to substitute node attribute calls into Puppet-compatible ones.
The converter will attempt to download remote HTTP urls into the correct output location in the Puppet module using Ruby's Net::HTTP module.