I managed to find a couple of notebooks such as this
http://library.wolfram.com/infocenter/Conferences/6540/ (Tricks from the master - Michael Trott)
http://library.wolfram.com/infocenter/Conferences/377/ (Robby Villegas on unevaluated expressions)
http://library.wolfram.com/infocenter/TechNotes/391/ (Rob Knapp on packed arrays)
I wish to know if people know links to more notebooks like these that focus on the core programming language. Please feel free to add more links below on Notebooks in the archive that specifically talk about the core language
Perhaps this can also prove beneficial to the community as well.
