RFC 3797 describes “a method for making random selections in such a way that the unbiased nature of the choice is publicly verifiable.” In other words, it shows how to pick an item or items randomly from a list without the person who controls the process being able to fix it. I used this mechanism to pick who was going to go on the OpenStreetMap trip to the Caribbean. The RFC includes C source code but it took me some effort to get going (it even has a bug). So I wrote a web application which implements the algorithm.
Feel free to use it if you ever need to make a similar verifiable random selection :-)