I could say that there were many highlights of the one hour opening act. But what I like most in that act (I think it mostly centered on it) was when they introduce the Chinese visual arts of calligraphy, printing and painting. Dancers made some patterns on a big size paper-like canvas (I really don't know if it is still paper or some other material as it is quite sturdy to carry some people on top of it) which turned out to be mountains and valleys. A part of the act made some children highlight the initial drawing with colors as a group of young men (I think in their teens) perform martial arts (I am not sure if it is tai chi as there are some fast movements).
With that I thought that the image was already completed. But once each country were introduced, they walked into something like a giant ink pad that added colors to the drawing as they walk along. Eventually, as more and more people pass by, a clearer picture emerges. The final image was then used as the stage platform.
Now the climax of the entire show I would say would be the lighting of the olympic flame. I already noticed earlier that they placed a small platform in one part of the stadium but I was wondering how would they light the olympic flame. Then the answer came with a magnificent and out of this world act. The torch bearer where lifted from the ground with a harness then raised up near the top of the stadium with the torch bearer moving his body as if he was running around and around the stadium as images of the torch's travels flashes in the background. The highlight was when the olympic flame was lighted with everyone in awe with its magnificence.
I remember the best olympic flame lighting ever (for me). During the 1992 Barcelona Olympics when an archer from the ground lighted the Olympic flame which is on top of a tower. A truly spectacular thing to see. Click here for video.
*UPDATE 13 Aug 2008 - Found this video in YouTube
* Beijing Olympic photos taken from Yahoo
Picture of platform from http://en.beijing2008.cn/