Chalk this up to the fact that sportswear trends generally hit the sleepwear market 1-2 years after they completely take over the fashion world. Sleep leggings are having a moment. I personally love the idea, but this is mainly because I am a lounge girl and wear my pjs to hang out in while I generally sleep in something much more like a tank top. Sleep leggings look cute with the drape-y, plush and cozy tops that also seem to be also taking over the sleepwear market. I was recently obsessed with the look and feel of the plush top (right) at my gym. So lounge-y. So sleepy. So perfect with sleep leggings. I predict everyone will be seeing lots of these in 2015.