Sorry I'm against this idea, if this is some form of fund raising for charity it should be taken to the Service board or any other board where previous charity have been carried out then it'll get more support and mine too. I'm very sure serious members won't associate with this. This only portray the idea of merit competition which I don't think it is hygienic for the forum. You don't create quality post with the idea of getting merited but as a contribution in regards to quality discussion in the forum, getting merited is just a bonus.

No hate but just imagine this, some random user accepts the challenge he/she now knows all eyes are on his account. what does he do, he takes advantage of that and goes hurting in regards to creating quality content and in return gets merits and ranked up. Then what?, We shouldn't encourage creating quality content just because they want to rank up (receive) merit but because volunteering we want to add value to the forum. If users use ranking up as their main motivation to create quality post, they become liability to the forum when they achieve that goals as the motivation will be lost.