One of the most popular short films on the Internet is Productive Nanosystems: from Molecules to Superproducts. The four-minute computer animation goes inside a personal nanofactory and demonstrates key steps in a process to convert simple molecules into a billion-CPU laptop computer.
Please note that the movie file is 47 MB (small format) or 75 MB (large format). It might take a while to download, but it's definitely worth it.
UPDATE: The new version of the nanofactory movie is also available from Google in streaming video. On my computer, the quality was lower than doing a full download, but if you don't want to wait, this is a good option. (Hat tip to Dino Fancellu)