Challenge: Make a Calendar

I was watching your regex videos at home a few nights ago, and at the same time at work I was trying to figure out how to generate a Calendar template (as a jpg file).

I ended up using a Photoshop script to do it, which I needed to edit quite a bit to get to work the way I wanted. While editing the script I noticed that the guy who wrote it also wrote a giant book on regex, and the script (basically JS) used quite a bit of regex as well - I think regex is how he was able to calculate everything.

I thought it would make an interesting tutorial - how do you figure out where in a grid the 1st of a given month is, how do you know what day the 1st is in a given future year, how many rows does a given month need, how do you draw a grid, how to deal with leap years etc.

the original script can be found here:
http://regex.info/blog/photo-tech/calendar

thanks for the videos!