This is me noting that I am still alive and am trying to post, though with limited success.
I had this idea while playing RISK a couple of days ago, mostly from a POW joke my friend made (I realize that sounds bad, but it was about the pieces, I had a couple of someone else's).
All of this is subject to playtesting, in that I thought of it and wanted to write it up.
I'll start with the POW rule I thought of, which can be implemented with little trouble, and adds some depth to the game. I hope. Basically, when you are attacking another territory, for each 6 you roll, you may take one of the opposing territory's armies as your own, instead of killing it, if you would have killed it normally.
The Zombies version is a variation of the POW rule in which one player controls the Zombies, but the outbreak starts after everyone else has already placed their pieces, so there is no knowing where the Zombies will be. I'm thinking that the setup will be the same as the normal game, just excluding the Zombie player. The Zombie player will then take a random card and repopulate that territory with Zombies by replacing 2/3 (rounded up)((or maybe something else)) of the existing units. The Zombie player will then choose two adjacent territories and occupy those as well, using the same method as described above. This could also be redone as having the Zombie player choose 5 cards and using those. Gameplay would be as normal except in the case of the Zombies. The Zombies would attack and take over territories in the same way, but when attacked, they do not get the defender wins ties rule. also, when moving into a new territory, the zombie attack force would lose 1/4 or 1/3 of its members, regardless of the outcome of the previous encounters. However, when attacking or being attacked, the Zombies gain all of the opposing dead (not their own) for their own 'infantry' at the end of the turn (no matter whose it is). These spare 'infantry' must be placed on the disputed territory. The Zombies do not, however, receive reinforcements at the beginning of the turn, so they need to kill opponents to gain anything. The Zombies are not, however, required to do anything during their turn.