Python
I'm mainly a perl programmer, but last week I've decided to explore the python language.
To keep my motivation high I've decided to use python for something useful to me: download every day my favorite web comic into the Pictures directory of my home directory on Mac OS X and keep it uncluttered by removing older episodes.
In the working of the project I've learned how in python to scrap web sites, parse XML with DOM, handling exceptions, manipulating the filesystem, doing time calculations, using regular expressions, ...
Python is quite cool, and I'm planning to further improve the application.
I'm still using the default Mac OS X python, the 2.3.5 without readline :-(
I'll try to install a more recent version with readline support.
Python 2.5 is tempting by I don't know if it is well supported yet by Trac, an open-source python project I'm intending to hack at some point.
I've added in my del.icio.us bookmarks a bunch of links that I've found helpful.