In Arthur C. Clarke's novel Rendezvous With Rama, the prologue describes a horrifying catastrophe in the year 2077: a large meteor impact in northern Italy which kills hundreds of thousands of people and destroys countless masterpieces of art and architecture. In response to the disaster, the people of Earth establish a project called SPACEGUARD to make sure it never happens again.
SPACEGUARD is here (71 years early!), although it has the slightly less butch title Pan-STARRS. The system will ultimately consist of four optical telescopes scanning the heavens for asteroids, comets, and (one assumes) interloping alien spacecraft.
Of course, right now if Pan-STARRS discovers something on a collision course with Earth there isn't much we can actually do about it. But at least we'd have the opportunity to live out all those end-of-the-world tell-off-the-boss fantasies.