42!

Day 20.  What would you do if 300 mice had just gotten out of their cages in a pet shop where you worked?

I wouldn't really mind that much. If I'm alone in the shop, I'd just make sure that the door is closed and I'd start collecting every single one of the. This sound very tedious but it's a matter of not losing the count because it will get even more tedious. As strange as it may sound, I'd treat them gently because I've read "The hitchhiker's guide to the galaxy" and I know that they're secretly ruling our world, waiting for the question to the answer of the universe to be calculated. 

However, if there are people in the shop, the job will become messy, especially if there are girls around. I'm not sexist but what's the problem with mice running around. It's not like they'll eat them or something. Again, I'll make sure that the door is properly closed and I'll try to calm down the customers while I'm filling my pockets with mice.