Using Eml2mbox Download eml2mbox (link in Resources), then double-click the downloaded archive to open it and drag the "eml2mbox.rb" file to the directory containing the EML files you want to convert.

The archiver, which dumps them into a .zip file, saves them all with filenames like 000400231.eml, which is pretty useless to browse through. Is there a way to do this? Am I just an idiot?

Better safe than sorry. Some file types stripped by my SMTP proxy are useless to the users (com, js, chm, cmd, cpl, bat, and 30-40 others). Useful ones that I strip are EXEs (no choice), eml and html.