Generate simple XKCD-style passwords using a master password and a domain name. Available as a GitHub page at kovaxis.github.io/pazzfraze.
This means that as long as you use the generated passwords frequently, you will remember both the master password and some of the generated passwords (at least those for your most commonly used sites).
All computation takes place on the client side, and to the best of my knowledge this should be secure, but there are absolutely no guarantees given with this page, and any loss that results from it is your own fault.