We've all got closets full of dumb clothing. I say "dumb" because it doesn't do anything, you just put on however much of it you need to be comfortable. The U.S. Army has had it with all these stupid bulky heavy layers of clothes, and wants someone to go out and invent something smarter.
The Army's proposal solicitation is called "Thermally Responsive Fibers for Environmentally Adaptive Textiles." The last half of that is straightforward enough: they want fabrics that can adapt to different environments. The interesting bit is the "thermally responsive fibers," which are supposed to be fibers that react to both external and body temperature by providing more insulation in cold weather and less insulation in hot weather (or if the wearer is hot). The fabric also has to be able to undergo a minimum of 500 thermal cycles, last through a three month mission, be hypoallergenic, and survive 20 runs through the washing machine.
The army isn't sure how to do all this, but if you can figure it out they're willing to give you a boatload of money. One idea is to embed tiny bimetallic springs into clothing fibers, where temperature changes cause one metal in the spring to shrink or expand more than the other metal in the spring, changing its length along with the thickness (and insulating power) of the fabric.
So, it can be done. Maybe. Probably. And after the army funds development of this stuff, there's nothing stopping it from going commercial, and we'll all be able to wear our three wolf moon shirts no matter how hot or cold it is outside. Victory!