Affordable ways to soundproof a sliding glass door?

[Zedaren]

So I'm renting a place with a buddy for a year, but my room has a sliding glass door to the backyard so I can hear anything that is going on outside. I don't really use it so I was thinking that I can put something in front of it and then attach some foam soundproofing egg crates. Thoughts or any other creative ideas?

[Randy S]

sorry for the delay, I missed this post..
Since you can not install a second slider the best you can do hang some Mass loaded vinyl in front of the door and tape the perimeter.
http://www.supersoundproofingsales.com/Mass-Loaded-Vinyl-45W-per-foot/productinfo/09-00005-54/

Randy S.