This story was only one or two pages - it appeared on a standardized test - and I'm positive that Ray Bradbury is the author.

The story was about a sickly man in a hospital, and a nurse repeatedly instructs him to be still. But when she's gone, he moves . . . and he makes a phone call. I wish I remembered more than I do, and I know that tons of stories probably fit the vague description I gave, but honestly, list them and I'll read through every one. The story was just great, and I'm dying to reread it.

Any ideas are appreciated.

This sounds like a chapter from "Dandelion Wine".
Scroll down to "Chapter 25-26, (The Window)" in this Wikipedia article and see if this isn't what you're thinking of.

http://en.wikipedia.org/wiki/Dandelion_Wine

Yes, Col. Freeleigh and the boys. "Rumble!"

Thanks, that was just what I was looking for Braling .

Br II, btw, that is a great link for DW via Wiki!

I was surprised myself!