Although Django is my preferred Framework of choice, the first moment I heard about all those MVC Frameworks and what they do was definately a "HOLY SHIT"-moment.
I'd heard about them for a while before actually getting in there and using them.
The first time I setup the django admin site was definately a "HOLY SHIT" moment...
Others:
* Google Sketchup (This was only last week --> It's so simple!)
* VM Snapshots
* ITunes library/playlist structure (Don't laugh... The unified library showing every song was a revelation after mucking around with winamp playlists and folders.. Also - I remember winamp really sucking on the mac at the time)
* HTML - "You mean I can publish stuff on the Internet and people can read it from across the world?" (I was about 11 at the time ('95))
