FleaPlus writes "NASA has recently announced a couple more X-Prize-style Centennial Challenges. The first is a Telerobotic Construction Challenge, for using a team of robots to assemble structures from building blocks with minimal human intervention. The second is an Planetary Unmanned Aerial Vehicle Challenge, to create a robot which can fly a path using visual navigation and hit ground targets with a probe (no GPS allowed). Rules are still being finalized, with the contests scheduled for 2007. Both prizes are for $250,000, the max Congress is allowing NASA to offer."