What is the MCU? (an explanation for non-nerds)
If you have been alive in the last 8 years, you likely have heard the term 'MCU' (Marvel Cinematic Universe) or at a minimum been inundated with the marketing material for the movies contained inside it.
The MCU, or Marvel Cinematic Universe, refers to the universe shared by the dozen or so Marvel movies and TV shows that have been released since Iron Man in 2008.
Why the term 'universe'?
To call these movies a 'series' would be underselling something that spans far beyond sequels and prequels. Each property in the MCU has the ability to impact other properties, or at a minimum, reference them.
I can't wait for the X-Men to show up!
Well, you'll be waiting awhile. It can get confusing but not all Marvel comics characters can be a part of the MCU. Years ago, before Marvel had the ability to produce their own films, they sold off the movie rights to some of their most popular characters. The X-Men and Fantastic Four can only be adapted into movies by Fox and Spiderman movie rights belong to Sony (lucky for us fans, they recently reached an agreement with Marvel/Disney to include Spiderman in the MCU). This is a simplification of the issue but a quick answer as to why not every character can be jam-packed into the next Avengers movie.
So who is a part of the MCU?
I had great aspirations of putting every Marvel movie poster in this post, but it would be out of date quickly and often, thanks to the Marvel machine. Instead I'll trust the good folks at Wikipedia to keep you updated for me: check out their list of MCU films and shows.