Deep Eddy
Argle Bargle or Foofaraw?
I've only seen a few of these things...usually opportunistically (i.e., I've wanted to go to the show, and these MCU films are often the least bad option). Most of these movies are reliable entertainment where nothing goes horribly wrong from a filmmaking standpoint...except for Iron Man 3 which I was dragged to and is pure garbage.
Mostly, these things are like big teevee. The plots are pretty much all the same, just reskinned to meet the needs of the characters in question.
Here's my recommendation for what to bother with...
Legitimately Good:
Captain America: Winter Soldier
Guardians of the Galaxy
Inoffensive/Mildly Amusing:
Avengers 1: Attack of the Money
Dr. Strange (not particularly interesting, but Cumberbatch is engaging in it)
Meh:
Captain America: Civil War
Substandard Saturday Afternoon Cable TV Movie Junk:
Thor
Iron Man 3
You can watch any of these films without all the continuity nonsense. A relatively smart 5th grader could catch on pretty quickly without the back story. Just believe in the POWER OF FRIENDSHIP and you'll be fine. But you might be tested at the end, where your sidekicks need to do a time-sensitive thing to unlock the power upgrade you need to complete the boss battle. Also, lots of shit will blow up and it will kinda remind you of 9/11, but not in a buzzkill way like those atrocious, stillborn DC Universe movies.
My son was watching Dr. Strange recently, and I saw most of it with him. I can barely recall the plot, but I think the cape is the best part of that movie. I'm not a comic book/MCU film buff, but I kinda hope Marvel creates a series featuring the cape. That could be fun.