The winning design will not only get the $10,000 prize, but will actually see their vehicle built as a fully-functioning concept. According to DARPA, "This is an opportunity for service members, race and auto enthusiasts, and those with an interest and talent in engineering, materials, industrial design, etc., to support the warfigther by contributing to the future of military vehicle manufacturing."
That last bit is particularly tantalizing. Local Motors' "open source" design concept took the car world by storm when it debuted a few years ago. The vehicle it spawned, the Rally Fighter, is a bit awkward-looking, but appears to be massively capable for its intended purpose: serious speed over rough terrain. Applying the idea to the design of military vehicles might seem contrary to the tenets of security and secrecy, but we're betting DARPA has that all worked out already.
Some of the early submissions are visible in the gallery above. To see how you can get involved in the XC2V challenge, visit the official page at the link below. The contest ends March 3rd, so there's not much time left to get a design together if you're interested.