I re-wrote my calendar utility (which tells me what my schedule looks like when I log in) in Python. This is good because I haven't touched Perl in some time and I wanted to add some other formats to it (like handling "second thursday" and "*/15") and I wasn't looking forward to figuring out what I wrote many years ago.
I also re-wrote my logger at work. It's not really a logger--it's more of a log extrapolator. It takes all these fun bits and puts them in places where I can glance over them quickly and guess at what happened rather than reading all the gory details and know enough to write a thesis.
Then I wanted to add a calendar to pyblosxom. So I adjusted the code to handle drop-in plugins and threw together a pycalendar thingy. It's not great but it works and it's not half-bad for an hour of coding.