Building a community site, with forum style and votes

I'm looking into building a site, which in many ways would be a clone of stack overflow... but not exactly of course (and with no intention of replacing or in any other way do something to harm stack overflow :-) )

What I'm looking for is a template, that will allow me to deploy a simple web based community site which allows users to: * Sign in * Post questions (or suggestions actually, so more like "wolfrevokcats") * Upvote "suggestions" * get higher "reputation" when people upvote their suggestions

Something like that.

Programming language does not really matter. I have basic skills in php and ruby, but I wouldn't mind having an excuse to learn the basics of some other language. I usually never get further than basics...

Can anyone recommend me where to start looking?

Thanks in advance!