It has been a long time since I was in college. That being said I would join that kind of club and if it didn't exist I would try to find away to start one.

I think atheist groups have a problem in that it is hard to keep a long discussion over not believing in something. Such a group woudl need to have some kind of focus, like the Freedom From Religion Foundation, which tries to insure that other people's religious beliefs do nto infringe on the rights of nonbelievers.

I think there is room for an organization that publicizes that the idea of religious persons beign more "moral" is actually a myth. On a per capita basis, most religions are over represented in prisonds, while atheists are very under represented. Evidently fear of hell isn't enough if you cna just confess and with great ease be forgiven.

I was a decently big part of promoting the chapter of the Secular Student Alliance when I was an undergrad at my university. Now that I'm a PhD student I don't have the time for it, and unfortunately the membership has dwindled considerably, and they're basically not operating anymore.
The best type of promotions we did were chalk advertisements. Everybody stepped over them as they walked to class, so they couldn't help but see them. Some of them got defaced, which was annoying, but we were diligent to fix them.

I am also long out of college, but I would also join and promote such a club if I were to be there again. I think actively inviting non members to come and say hello and join in discussions would be the first way of getting new members.