Give away something men are interested in, in return for articles/threads/posts on manly subjects? In one of your older threads theres loads of suggestions for things you could use to give away
Maybe they can make content on how to keep the body 'in shape', what they think are jobs for a 'man' shizz like that. You're a man, no? Ask yourself what you would like to read about, that interests you that can be seen as 'manly'.
If you are requesting the competition, then you setup the criteria for the content. What are you interested in having put forth, if something specific? Or will you leave it up to the hopeful contributors? Who has the best cell phone? Explain why in x words and use pictures. etc.