Car blowing small amounts of blue smoke? Help!

What is your question?

It started about a week ago. It sporadically blew blue smoke, small amounts when going at slow speeds, stopped for a few days, then started a couple days ago again; last night it's doing it while idling. Again, very small amounts. No engine lights. Either piston rings, valve stem guides, or PCV valve? What else could it be? I'd like an estimate before I take it in :(