Ok, so maybe it's a little cliche to be a crafter and to love Martha Stewart, but I'm admitting it. Right here. I heart Martha Stewart. Maybe her extensively detailed articles on the proper laundering techniques of bed sheets or pruning apple trees can get a little tedious, but sometimes her crafts are so right on.
This craft is not actually hers (but really, which ones are?); it's by Jodi Levine, one of her craft gurus. (I swear I saw Jodi at the new Michael's here in NYC, but I was too craft-struck to say anything.)
Instead of sending disposable paper greetings, she made these very easy tissue packet holders from felt (my fave source for wool felt is Magic Cabin) and stamped the top tissue with a sweet greeting. Easy, flat, and perfect for winter.