Mock fire-fighting: Do you do downtime drills?

Being a DevOps engineer, deep deep down in your heart, no matter how stable your tests are, you sometimes wonder if production is going to break when you deploy.

I was thinking of proposing a mock fire-fighting drills in the weekends. Like one of our engineers will take our test environment down and I will try to bring it up, so that when production goes down I will be acclimatised to handling it in a nice way.

Do any of you do this or is this a complete waste of time?