If you have not come across it, the challenge machine is a web based way of easily creating quizes that can be done online. You can challenge classes or friends or anyone and you can rack up points scores. Here is a simple example...
The challenge machine is an easy way to create a quiz online that you can share with others. When you log in you can rack up points for yourself and so on. It is very good. Lots of potential for students to challenge each other and teachers to set challenges for classes. It is also wider than that though and the challenges are published to all users. Uses could be to ask opinion, conduct surveys, I don't know.