If you really wanted a Chaos Challenge, you'd play Calvinball rules...

Or a massive figurine battle. Put in your figurine, whomever comes out on top wins.

I assumed by lack of reply that rules are coming up or may still be in deliberation.

Sorry, you want rules and regulations in a challenge of Chaos? ;)

Even if we don't want them, they'll probably be there anyway :P

Have there been rules previously? If so, what were they?

I've never really taken part of Chaos, but the standard rules seem to be no inside, no magical movement, no org-territory (which might include villages?) and such.

No spamming maze?

These are the only hard-coded rules, as far as I can see:
1) Glamours Maze cannot be used on the individual holding the Chaos Hamster.
2) Any major movements by the person holding the Chaos Hamster will cause it to disappear (eg teleport).
3) If you drop the Chaos Hamster or try to give it to another person, it will disappear to another place.
4) If you have grace while holding the Chaos Hamster, it will disappear to another place.
5) Being at any elevation other than in the ground or the trees will cause the Chaos Hamster to disappear.
6) Holding the Chaos Hamster will prevent most forms of elevation change.
7) Holding any hamsters other than the Chaos Hamster will cause it to abandon you in a fit of jealousy.
8) Standing in a room that is not on the Prime Material Plane, or is affiliated with a City/Commune, or is a newbie area, or is indoors, will cause the Chaos Hamster to disappear to another place.

Calvinball it.

One that I missed: if the Chaos Hamster is given to a mobile, it will disappear to another place, so you can't use delivery pets to give it to another person or give it to a pooka for safekeeping.

Kialkarkea:

Calvinball it.

Better idea. Make a wheel that has random rules to add or remove on it and spin it every 10 minutes or so.