Back in the day http://eye4u.com had by far the most amazing flash animations of any site I'd seen. I don't know how they did it but their animations were next level for that time period.
This is the site that got me into designing flash. I was so entertained and thought every website should have an intro like that. Build one for our website, not anywhere as close to professional, and realized how annoying it was to wait for that animation every time I loaded the site.
Apparently some of them are on youtube now:
https://www.youtube.com/watch?v=3aT4wt0fmGU
https://web.archive.org/web/20041126020223/http://eye4u.com/