Karthik Ram gave an Introduction to R a couple of weeks ago, and I strongly recommend you to take a look at his cool HTML5 slides. I started trying HTML5 slides last year, and now it is difficult for me to go back to beamer, which I have used for a few years for my presenations. It is horrible to see beamer slides everywhere at academic conferences (especially the classic blue themes).
You probably have heard of an interesting blog post by Ben Schmidt about ocean shipping animations in the 18th and 19th centuries. I also played with the dataset a little bit, and made some slides named Voyages of Sinbad the Sailor (use Left/Right or Up/Down to navigate). The source file was written in markdown, compiled by knitr, then converted to DZSlides by pandoc.
I'm using the development version of knitr, which you can install from Github. I plan to release the version 0.5 this weekend, and this version will particularly feature the markdown support. You can always read the NEWS file to know what is going on in the development.
Another piece of news which may be a little bit early to announce is the corresponding support in RStudio. I'm not going to say any details about it right now, but I'm pretty sure the so-called reproducible research and dynamic report generation can be easier than ever very soon! No LaTeX. No worries about HTML/CSS. A simple text file and a single click will give your a reasonably beautiful HTML page. Stay tuned.