Flip Tanedo (along with some of his colleagues) from the US/LHC team has posted an excellent series of tutorials on the Standard Model at the Quantum Diaries blog. Non-mathematical in nature, this series of blog entries systematically delves into some of the deepest mysteries of theoretical physics in an exceptionally accessible manner.
At the core of these tutorials is a series about understanding the Standard Model via Feynman diagrams:
There is also a short series on the importance of symmetry in physics:
And here are some links to a handful of miscellaneous yet fascinating posts which don’t fit into either of those series:
But wait! Flip isn’t the only working physicist out there with excellent tutorials. Here are some by Prof. Matt Strassler of Rutgers University:
[Please note that I’ve been adding links to relevant articles as they have appeared, so don’t be terribly bewildered if you follow a link and find that it is to an article more recent than this post.]