Having been out to Assembly a few times (not in the last couple of years though, flying to Finland is just too much hassle now days), I have to say that there is very little that can compare to the atmosphere of 1000s of computers inside a huge arena, screens lit up, no other lighting... and then these demos playing on the huge screen. Great event.
This was my first Assembly (I know, I'm late) and it was absolutely inspiring. These demos take months of work, and they're done for fun -- sure, there's some rivalry there, and there's a challenge, but it mostly seems to be about creating art and having fun. It reminded me why I started programming computers in the first place.
Glad to hear you liked it! Were you there for any particular reason or just for the experience?
Pro tip: don't go to the Winter Assembly, it's no where near as good as Summer ;)