How can I score a code golf challenge, with added complexity?

I've had a couple challenges in mind that are somewhat along the lines of:

Do x in as many ways as possible, with as little code as possible.

However, I'm having a hard time settling on how to score this. I'd like a way that gives fair weight to the "many ways" factor while still very much encouraging a mentality.

I've already seen tags or suggestions for "code chess", "code bowling", "atomic code golf", etc - most of which seem to not have gone over well. Is this a similarly bad idea? Or is there already another name for it, and a standard means of scoring?

• Can you objectively define whether two programs are solving the task in the same way? – Peter Taylor Nov 26 '13 at 12:06
• @PeterTaylor Yes. Wouldn't be a really fair challenge if you couldn't. – Iszi Nov 26 '13 at 13:57

  number of ways

• If I'm reading this right, the higher score should win? My first thought was actually the inverse - characters/ways - and low score wins. Any thoughts on problems I might encounter, or should avoid, other than the 1-3 character thing? – Iszi Nov 25 '13 at 19:48