The Military is wanting a new amphibious tank, but also wants new ideas that can't be had from the same old stable of military contractors. As such, DARPA is asking people to participate in a crowdsourcing contest, with two $1 million prizes and one $2 million prize. What you're designing is an amphibious, infantry fighting vehicle, because sometimes dudes with guns need to come out of the ocean.
The design of military vehicles costs untold millions, or even billions of dollars in some cases, so from a taxpayer's point of view we're certainly happy that all that is being spent on this is a paltry $4 million in prize money.
We're thinking we'll send in a sketch of Optimus Prime.