The majestic ice rings around Jupiter, Saturn and Uranus do not surround our dear planet or we'd of course see them. But some interesting facts abound:
It's possible that there were rings orbiting earth in the past. Astrophysicists believe that earth's intense gravity broke up a comet or asteroid that got too close but didn't collide. This is very similar to what happened recently to Comet Shoemaker-Levy 9 when it eventually crashed into Jupiter. First the gas giant tore the comet to bits, then pieces crashed to the surface on a later orbit.
In the case of earth, it might've held onto a few ice particles from a comet, which would then have orbited the planet and eventually crashed into our atmosphere and burned up. Even the very smallest of particles of ice or dust create spectacular meteors in the sky - if there was even a tiny ring now, we'd see these impacts all the time.
Other scientists believe that a giant asteroid impacted with earth, like the one from the Cretaceous Tertiary period which wiped out the dinosaurs, leaving only small mammals to survive. This would've kicked up a huge ring of debris around the planet that would cast a shadow on the earth, changing our climate, and could last a few million years at most.
who thought this up....
Finally, get this: Humans have put up an artificial ring around us in the past. And surprise, surprise, it was the US Military complex. 480 copper needles were launched into earth's orbit in something called Project West Ford. Scientists could bounce radio signals off the needles and communicate between two locations on earth. This actually worked for a few months, until the needles became too dispersed to work.
It's all science. Right?
Some basics courtesy of JPL, NASA, Science Today, Gryphon.