I love this one, Improve Code by Removing It:
<a href="http://programmer.97things.oreilly.com/wiki/index.php/Improve_Code_by_Removing_It" rel="nofollow">http://programmer.97things.oreilly.com/wiki/index.php/Improv...</a><p>Looking at my git stats, I've deleted about 20% more code than I've ever written (in fact I've deleted more lines than all but one of our devs has contributed), and the site is certainly a lot faster now than when I started.