It could be really funny if you combined this with my challenge of
Lois proposing first. That way, Clark has to come up with a way to try to either propose first (before her) or (if that doesn't work) to then TELL her first about being Superman in a way that doesn't stop her from wanting to marry him. (This also works, if he proposes badly -- i.e. without telling her first -- and so he keeps redoing it until he can get it right.)
After successive mishaps and redos (as what happened in 'Twas the Night before Mxymas), Lois starts to get a case of déjà vu, where suddenly things start to seem familiar.