I am interested in learning and using radare2 as a toolset for reverse engineering. But I want ANY other resource for learning this tools other than radare2 book, preferably a video series. What I am interested in is solving crackmes and executables debugging.
I think this is what you are looking for: https://github.com/maijin/workshop2015
And of course just join the chat room on freenode #radare2 and ask questions.
We collect useful links about using radare2 on our forum (jvoisin blog too :) )