WonderHowTo: hand-selects and curates the best instructional videos from over 1,700 websites.
This site has a HUGE collection of video tutorials about all themes you can imagine!
I definitly must have a lookat Math and Teaching categories.
PickTheBrain, a website dedicated to self improvement with a focus on personal productivity, motivation, positive psychology, and self education.
JFLAP is software for experimenting with formal languages topics including nondeterministic finite automata, nondeterministic pushdown automata, multi-tape Turing machines, several types of grammars, parsing, and L-systems.
> JFLAP Tutorial
(Spanish) Para aprender y mejorar el uso del inglés (tendré que buscar tiempo para practicar el inglés hablado, y tampoco me siento seguro con mi nivel de escritura 😕 ).
Finally, almost three years after I wrote this post, I decided to switch off the sticky marker, so that it is no longer shown in the front page. Nevertheless, I still think the webs linked here are terrific sites with tons of useful information!