Promotional flicks for webcomics, anyone? Something like this unofficial advert for Dave Hopkin's Jack.Pop videos for books? It might sound like an uncomfortable marriage of media but short online promotional films for novels are being seen as the latest marketing tool by an increasingly web-savvy book trade.
I don't know how seriously I take the idea, but it's fun to think of. You'd be less likely to want live action, so Flash would probably be ideal: it gives fairly small files so it's less dependent on broadband, it's pretty easy to learn, and it can take a wide range of animation styles.