This article in InfoWorld discusses Kontiki's grid based content delivery system.  The basic concept is Napster with an eye to what enterprises need.  They've taken it one step further and removed the user from having to decide which peer to download from (remember the traffic lights on Napster?) so that downloading from the system is transparent.  Just point and click.  When people talk about "grid computing" the analogy is usually something about computing utilities, but this is a real world example of a grid solving a real world problem: file downloads.  So, next time you hear grid, think content delivery.