I've looked through the list in Stack Exchange clones, but it seems that Stacked is the only one available mentioned there, but it does not seem to be active.
I would be very eager to contribute to the open source version of an active ASP.NET clone of Stack Overflow.
Stack Exchange has a qualifying process and no-ownership policy. I would like one where I can make all kinds of necessary changes and commit it back to the main source. But I don't want to rally a community behind the Q&A before I can use it. I'm sure there are a lot of businesses out there who want a Q&A on their Website. Whether the community will thrive or not, sometimes it is hard to ascertain without putting it out there first. For example, my website has a niche which may take years to build a community. But that doesn't mean my Q&A is less relevant when there are not enough people rallying for it now. It is just that it may be ahead of its time for now.
Thank you all.