Prize?
uhhh....
The satisfaction that you are a good and knowledgable PHP programmer

I dunno
I wasnt thinking on a scale like that, but like you see how different people think of different way to do things. They can learn algorithm analysis, get practice using PHP in every day applications, and get interaction and comments from other "expert" PHP programmers... stuff like that.
I guess it would require some free time from different people, something im assuming not very many people have here

Would build a nice code library though.
I dunnom just a idea
Will