"Why?"

Okay, my darling daughter has hit the "Why?" stage - and much sooner than I had anticipated! She's been asking, "Whatcha doin'?" for a while now. (I have to say it was quite entertaining when she went with me to the gyno a month ago and the dermatologist last week.) I knew this day would come but didn't know it would be so soon - most say their child hit this stage somewhere between 3 and 4, not 2! A few weeks ago she started with the whys but now it's with everything, everyday. I'd love any suggestions on how to handle all the questions. My husband and I started answering each question but by the end of the day we want to pull our hair out - as you know, one why leads to another why... Any suggestions???