A nice list of lesser-known algorithms that are useful in system design.
A primer on the out-of-kilter algorithm written for the US Air Force as part of Project RAND.
A nice course from Stanford on modern applied algorithms with all course notes and assignments available online.
The Complexity Zoo, which maps out the connections between all different complexity classes.
“Matters Computational”, a very interesting collecton of information about methods of computation which “does not usually appear in textbooks on algorithms”.