Here is another one of those things that can help you through the day when your supposed to be working. Previously I posted a link to how to build the perfect paper airplane. This time its how to build structures with coins using no glue. The author of the site based it on a presentation he gave "while a Civil Engineer at Texas Tech University in 1980".
Have a browse to the other pages where people have posted pictures of their structures, some are basic but others defy gravity. You'll be amazed.