When I first heard of Zen Coding on Sitepoint, I figured it was some other gimmick that might save me about 0.01% of my time each year after I spend five or six hours learning the syntax.
Zen Coding works by expanding some abbreviations into properly closed html. The syntax is very simple, and can be easily explained in just a few examples. The syntax is basically CSS selectors which most web designers / web developers should already know.
Overall, I found installing and using Zen Coding to be very worthwhile. I just made sure to change the shortcut key in Notepad++ because Ctrl + E wasn’t doing it for me.
Ports exist for a lot of different editors, and IDEs, so check it out. What other productivity tools do you use?