AT - Autogenous Training
before i tried AT i thought it was something esoteric, but now i think it's really worth trying it.
i once bought an AT learnig book/CD, and didn't even finish all the chapters, but it was a great experience to learn how you can influence your body. so it can help you to learn some rituals which help you to relax, but first it will make you realize that you can influence parts of your body without doing anything but relaxing and a bit concentrating and some minutes of your time.

things that also help me (during work):
- headphones with my favourite music
- playing a party of online chess
- have an irc window open with your favourite irc channel where you can rant about the current bug you're trying to find whenever you need to (and hopefully hear some "i know what you mean" from others)
- don't take work too seriously. yes, it's necessary to feel responsibility about your work, but whenever possible, try to remeber, you are not your work, it's just a part of your life
- perl (yeah, now we're ontopic again). it's fun programming Perl, oneliners, JAPHs and perlgolf. it's fun because, like merlyn said in this post: "Because Perl's so durn easy to use we got time to play around impressing each other. :)"