Once again, Boing Boing provides much entertainment:

Anti-comet airbag plans. A scientist in Oklahoma is planning to build giant, anti-comet airbags that can be sent into space and inflated to deflect the course of world-threating lumps of celestial rock.

Far better to send up a space ship equipped with a massive airbag that could be inflated to several miles wide and used to gently buffet the invading solar body away from a collision course with earth.

"It seems a safe, simple and realistic idea," Burchard told the magazine's latest edition.

I can just see the space shuttle with a giant ballon in front of it ramming a comet.