Website: https://opensecuritytraining.info/Welcome.html
Disclaimer: This site has undergone a re-design branded as “OST2” that has fewer classes and asks you to sign-in. The link referenced here takes you to the older version that does not require sign-in.
I do not know how long that original version will be up, but it had 29 classes comprising 63 days of materials on everything rom intro to network forensics to in-depth looks at keylogging on Windows.