That swisstrains thing is really cool. I have usually heard of these things described as a “mashup”. Using RSS feeds or other public APIs, developers mash two or more things together to make a new way of looking at data.
When my wife was scouting locations for her optometry practice, we came upon one which overlaid census data and zip code regions on the Google map, and showed you the most populous Zip codes by making their codes larger font-size, similar to the tag cloud on Flickr.
What’s really amazing is that often these things don’t require a lot in the way of programming to get going, because the developers of the various services have provided a rich API that allows mixing and matching.
Have a google at ‘mashup’, and see where you go from there. It’s probably not going to be something that you’ll see an Action for, but it may be easier than you think to make one of these for yourself.