Adobe Flex?

Does anyone know exactly what Adobe Flex does, I've heard so much about it in the last month, but I'm still a little unsure on what it does. I know I it implements AS3, but then at the same time it also takes advantage of AJAX (which I dont really know a great deal about). What I've kind of been hearing is this is the next step in the web, and allowing for more user interactivity, but when I go and look at the examples the Adobe has to offer on there site all I see is stuff that I could easily do within Flash, but with a completly different code, one that resembles more HTML then actionscripting, but I still see some action scripting within it. So is this what they are hyping it up to be, is this something I should think about making a new site out of, or just something that I might want to add a little bit of to my site, but keep mainly with what I have already, and what exactly is it going to be used for, is it a step towards getting rid of the classic HTML sites (to an extent) and also what is this Apollo, have very little info on that, but people saying "it's the next big thing", which gives me no clue to really what that is.

I heard about flex, but wasn't really interested of what it can do.
flex intro

But about Apollo, never heard of it untill now. After a little research:
what is apollo
Seems like Adobe wants to make some sort of application (they say cross-operating system runtime ) that will allow the communication between Flash, Flex, HTML, JavaScript, Ajax. Probably something like java runtime which allow users to run applets in the browser, but this one will allow more interactions.
If i say stupid things someone correct me

Apollo looks like a cross-OS version of Microsofts HTA (HTML Applications) to me.
That is, if you don't have to compile anything.