I just found a really good map mashup for the greater New York area that shows the locations of all of the Relay For Life events on a map. Creating mashups like these are neat for visual learners and those who like to see where events that are taking place are close to them.
As mashups continue to proliferate we will see additional medias being combined. Sharing Hope .TV is a site that encourages users to upload their own content about their cancer experience. Best part is that the site allows constituents to license their content Creative Commons. All of this is important to seeding mashups.