CS/ECE 374: Useful Resources

Illinois course materials
Lecture notes, slides, lab handouts, homeworks, and exams are available for several past semesters of algorithms classes at Illinois. For each class, I've listed only the most recent iteration for each instructor, but several older semesters are also available.
Course materials elsewhere
Sadly, it has become significantly less common for instructors to post their lecture notes/slides, homeworks, lab/discussion/recitation handouts, and other course materials to the open web. Most instructors either lock their course materials inside walled gardens (Piazza, Moodle, Stellar, etc.) or simply delete them when the course is over. Here are some useful exceptions.
Both Coursera and Udacity offer complete algorithms courses, with videos, readings, and automatically graded exercises. By necessity, these courses tend to focus more on implementation and less on proofs and open-ended design than CS 374 or 473.
Free Online Textbooks
Hopefully this list will continue to grow.
Dead Trees
For students who prefer an actual dead-tree reference, we recommend the following textbooks. The campus bookstore probably doesn't have them, but they're cheaper online anyway. And they're all in the library. You remember that big brick building with the coffee shop and the study tables in it? Yeah, they have actual books in the basement.
Book? Wake up and smell the Internet, grandma!
For review of prerequisite material, we strongly recommend the following online resources. (This stuff is also covered in several dead-tree textbooks, but really, why bother?)
Programming contests
...which (at least at the advanced levels) are really algorithm design contests where you also happen to write some code.
We'll add more links here as we discover them. Suggestions are welcome!