Please use my talk page to communicate with me about Wikipedia rather than e-mail; I more likely to read your communique if it goes there, and definitely more likely to respond.
Twelf - Popular logical framework implementation (plus metalogical tools) used for formalizing logics and programming languages. (I use it in my thesis research!) The article still needs to be fleshed out a bit.
((nofootnote)) is a useful template I can never remember the name of.
I usually head to URLs directly by typing them out, but that doesn't work with Category:Articles that have been proposed for deletion but that may concern encyclopedic topics
PeriodBot
I've written some software in SML for mining Wikipedia off-line. One early application is PeriodBot, which searches for article paragraphs that don't end with punctuation (an incredibly common mistake). We manually apply these changes as part of Wikipedia:WikiProject Punctuation. (Since this program doesn't automatically interact with the live wikipedia either to read nor write, it doesn't really qualify as a bot as per WP:B). You can get the source code here if you want.
Since then I have been more interested in extending the Wikipedia interface using Javascript (ugh) to automate repetitive editing tasks, particularly as respects my superficial editing interests (punctuation and typography, image formats). These are not quite ready for prime time yet, but please ask if you're interested in beta-testing.
I also frequently run my autopunctuation script on featured article candidates and featured articles. If you're working on an article that you would like to have high quality punctuation (particularly en dashes), just leave a message on my talk page and I will run it on your article. (example)
Images
I like taking photographs, and I've uploaded some images to Wikipedia, too. I occasionally replace poor pictures with better high-resolution ones; when I do, my policy is to use a license at least as generous as the old one.
As an image quality stickler, I also spend a lot of time tagging and converting images to better formats, especially SVG. Unfortunately SVG thumbnail support is pretty unreliable so some of these don't even show up. Does anybody know if I can do anything to make this situation better?