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"Context-free" is a relative term. Most context-free parsers actually parse a superset of the language which is context-free and then check the resulting parse tree to see if it is valid. For example, the following two C programs are valid according to the context-free grammar of C, but one quickly fails during context-checking:
int main()
{
int i;
i = 1;
return 0;
}
int main()
{
int i;
i = "Hello, world";
return 0;
}
Free of context, i = "Hello, world"; is a perfectly valid assignment, but in context you can see that the types are all wrong. If the context were char* i; it would be okay. So the context-free parser will see nothing wrong with that assignment. It's not until the compiler starts checking types (which are context dependent) that it will catch the error.
Anything that can be produced with a keyboard can be parsed as context-free; at the very least you can check that all the characters used are valid (the set of all strings containing only displayable Unicode Characters is a context-free grammar). The only limitation is how useful your grammar is and how much context-sensitive checking you have to do on your resulting parse tree.
Whitespace-dependent languages like Python make your context-free grammar less useful and therefore require more context-sensitive checking later on (much of this is done at runtime in Python through dynamic typing). But there is still plenty that a context-free parser can do before context-sensitive checking is needed.
I don't know of any tutorials/guides, but you could try looking at the source for tinypy, it's a very small implementation of a python like language.