I've found that keeping little toys on the tech table helps kill the stress during production meetings and particularly gruesome rehearsals. I usually keep a little slinky, a couple of hacky sacks, some silly putty and a miniature etch-a-sketch in plain sight for frustrated people to pick up and play with. Playing cards don't hurt either, especially if there are large casts or children about who need to be kept entertained and quiet when they're not being staged in.