I'm just starting the "50 Shades of Grey" trilogy - and can't help but think that the general idea would work out quite nicely for LnC. And, since there are so many great and talented nfic authors around, I wanted to propose this challenge:
Write an LnC fic that involves the general theme of the "50 Shades" trilogy. Whether it's a 50 Shades of Luthor, 50 Shades of Kent, 50 Shades of El or even a 50 Shades of Lane fic is up to you. (Heck, I'd even go for a 50 Shades of Cat!) However, the people involved in the relationship should be two of the returning characters of LnC.