As any armed forces member who's served in the Middle East can tell you, it's ludicrously hot there—even without the additional 50+ pounds of clothing and armor. That's why the DoD is offering cash money for some "Thermally Responsive Fibers."
The DoD has issued a Small Business Innovation Research solicitation for the design and fabrication of "Thermally Responsive Fibers for Environmentally Adaptive Textiles." These are fibers that adapt the amount of insulation they provide dependent on both the external and body temperatures. Essentially, it's got to be cool when you're hot and warm when you're cold. The added bonus to soldiers is that the fewer layers worn increases mobility and freedom of movement while decreasing weight.
To qualify, garments fabricated from the fibers must also be hypo-allergenic, as well as sturdy enough to survive 500+ temperature cycles, a 3-month mission, and twenty wash cycles. The initial Phase I solicitations have a maximum value of $1 million. [US Army via DVice - Top art courtesy of the AP]