Chex mix seems like it has been a party food staple forever, but in fact it was only invented in 1952, when the recipe began appearing on the back of the box.  Chex mix was almost a diabolical invention in the way that it requires you to purchase three entire boxes of cereal in order to complete the recipe.  But you know that it isn't going to be as good if you don't!  (I have tried making Chex mix with only one kind of Chex.  It did not turn out well.)

Chex mix also occupies an interesting historical niche as being one of many "TV mixes" which were invented in the 1950s for people to eat while watching that newfangled television.  Most of these snacks were brand oriented, as you might expect from the heyday of brand recognition and faith in the corporatized food supply.  (Kix has nutrients!  Cigarettes relax your lungs!)

Technically if you make Chex mix yourself, you are making "Chex party mix."  The name "Chex Mix" is officially reserved for the pre-bagged Chex mix that you can buy at the grocery store.  These mixes come in a variety of flavors, but if you ask me, they all taste the same (i.e. like salt).  In addition the pre-made mixes are expensive, although perhaps not as expensive as buying three boxes of cereal, considering today's cereal prices.

Regardless, homemade Chex party mix is far more delicious than the commercial Chex mix.  And probably better for you, considering the breadth and depth of artificial flavorings and preservatives in the commercial bagged Chex mixes.  

I found the original historical Chex party mix recipe thanks to Wikipedia, in the form of a magazine ad scan.  (This must have been back in the days of yore, when recipes in magazine ads were actually tasty.  Have you seen some of the recipes in magazine ads today?  Half of them make me want to retch just reading them.)  This is also the simplest Chex mix recipe I have seen, as it calls for just butter, Worcestershire sauce, two cups of each Chex cereal, "nuts," salt, and garlic salt.  

This, I feel, is the One True Chex Mix Recipe.  It's what I remember my grandmother making at Christmas time.  (She insisted on using Spanish peanuts, with the assertion that they were "the fancy kind, for company."  And always served her Chex mix in a large porcelain serving dish shaped like a banana leaf.)  I have found a lot of other recipes which claim to be "the original," but clearly are not.  Unless I'm wrong, and it was actually possible - nay, easy - to find bagel chips back in the 1950s.

General Mills ran a survey recently (one which I'm sure was completely unbiased) which found that Chex mix is "America's favorite," but Muddy Buddies were the next runner up.  This is basically chocolate Chex mix, a cousin to the classic 1950s haystack cookie.  Instead of using fried chow mein noodles for the structure (as with haystack cookies), Muddy Buddies use Chex cereal.  The classic Muddy Buddies recipe can be found here on the Chex website.