reconcilable differences by shallot; 40.113 words
Smallville: Clark/Lex.
So, you know, comics canon is far more invested in crack fic than fanfiction could ever hope to compete with. Shallot makes use of one of my favorite bits of DC canon wtf-level crack: Kon, aka Superboy, who is the test-tube baby of Superman and Lex Luthor. No seriously. In DC comics canon Lex Luthor and Clark Kent have a baby together. This story is fabulously funny and wonderfully long; no previous knowledge of DC canon needed to enjoy.