Looks like I'm fashionably late to the Pinterest party (yes, I finally joined today; I'm "Shannonmarie of Rawdorable"), so I needed to find something suitable to wear. I quickly put together another DIY (check out my Instant DIY Catbird-Inspired Earrings, if you missed them earlier today), this time out of my son's white t-shirts.
My son has been growing like a weed (seriously, he's my height or taller). When he outgrows his plain white t-shirts, I make them into play dresses for Hayden, although now I can transform them into something that fits me, too.
To make my spontaneous t-shirt dress, I used two size x-large boys white t-shirts (Jacob has moved up to size small in men's). I start by making a skirt out of one of the t-shirts. I just step into the collar and pull it up around my waist. The collar will stretch a bit, so I don't advise wearing it as a shirt again.
Then, I tuck the sleeves in, as shown, to create "pockets." If this truly is a spontaneous dress, you probably won't be able to actually put anything in your "pockets," as they will be open at the bottom. However, you can opt to sew the bottom of the sleeves/pockets shut, if you want functional pockets.
To make the top of your dress, simply put on the other shirt and loosely tuck it into your t-shirt skirt. You could also cut it into a crop top, depending on the fit of the shirt. How's that for spontaneity? Okay; so maybe you might want to get the wrinkles out before you go out anywhere :)