Good Riddles

Question: What was the calendar so cramped up and going crazy?

Question: I have two rings. I move by request. If the mixture isn't right I just sit and rest.

What am I?

Question: I do good things, but one small push could be a horrid disaster! I am normally used for decoration now.

Question: When the answer I give is yes, it is no, and when the answer I give is no, it is yes. What is the question?

Question: Where do all the letters sleep?