Just finished a 4-5 hour game with a few friends and we tried a new approach to fire that was discussed here - a Warhammer 40k dice with arrows to control which direction fire spread from all burning spaces. It worked really well; we couldn't rely on it and it had a mind of its own. So that might be something other folks want to try for a variation.

That's one idea. I've been thinking about a d10 dice. 1-8 are different directions, 9 means same fire spreads in two directions (roll 2 more times), 0 means that when the first fire spreads the new one continues to spread (roll 2 more times).

But then I don't have an arrow die...

Admittedly it took my getting a d10 out to comprehend, but it makes perfect sense. Good idea! After hours of playing, I wouldn't trust myself to use anything more complicated than an arrow on a die, though - we were the real zombies by the time the game was through