I added a feature in IlohaMail to publish one's calendar, and to take it one step forward, decided to look into exporting to iCalendar files ('cause then I can import my schedule to my iPod). If I limit to just supporting portions of the format that's also supported in IlohaMail, it doesn't look too bad... except for one thing: VTIMEZONE.

In iCal, timezone information is specified in a VTIMEZONE component, which basically includes timezone offsets for both standard and daylight savings time. So far so good. But where it gets complicated is that VTIMEZONE understandably also wants to know when daylight savings time starts and ends. That is a huge problem, because different time zones (and even regions within the same timezone) have different rules as to when DST begins and ends (which, in extreme cases, changes from year to year). In other words, as far as I can tell, there's no algorithmic solution to this problem.

From what I've discovered, there's a fairly extensive database, commonly known as the Olson Timezone Database. You can then use a nifty program called VZic to convert the data into Outlook-compatible iCal files. All I have to do now is include the compiled VTIMEZONE data in IlohaMail (which'll add about 22k targz'd), get the appropriate region information from the user, and include the appropriate file.

Moral to story: time zones are a bitch. Now I understand why the Swatch Internet Time was conceived of to start with...

An awesome colorization algorithm (via evan_tech):

Our method is based on a simple premise: neighboring pixels in space-time that have similar intensities should have similar colors. We formalize this premise using a quadratic cost function and obtain an optimization problem that can be solved efficiently using standard techniques. In our approach an artist only needs to annotate the image with a few color scribbles, and the indicated colors are automatically propagated in both space and time to produce a fully colorized image or sequence.