Captain America was trying his best to get a cat out of a tree when a muscle spasm caused him to twitch into a particularly inhabited hornet's nest. That's not where he died though. The hornets chased him onto a construction site where another muscle spasm caused him to fix himself to the wall with a loose-triggered nail gun.
That's not how he died though. He lasted there through the winter, but when the spring thaw came several winged creatures melted back to life in a cave, they flew out and found the good Captain in a very hungry but attractive state. That's not how he died though. The monsters made him pregnant, and upon child birth he couldn't dilate all-the-way because he's a man.
A few days later he died in a hospital bed with several pieces of drywall still stuck to his forearm and thighs, and stitches in secret places. And that, we have on good authority, is how Captain America died. Or he got shot by a malicious sniper, we've never been good at reading speech bubbles.
Marvel Comics has seen to it that Captain America, defender of a whole bunch of nice sounding things, has given up the ghost. Marvel killed him off on a bunch of steps, and after all his intergalactic superhero-ing, it was a simple bullet that did him in. Marvel's website explained it like this:
"Steve Rogers, better known to the world as the star-spangled Captain America, lies dead, having been assassinated on the steps of a federal courthouse. Being led to trial for violating the Superhuman Registration Act and engaging in the Civil War that pitted super hero against super hero, Rogers was senselessly taken from a world that he had helped save countless times before."
Don't be blue all, it looks like this leads to a comic book mini-series:
"The ramifications of a loss this huge could only be told in a five part event: Fallen Son: The Death of Captain America. Each chapter will follow different Marvel heroes and chronicle their reactions to this loss, the first two spotlighting Wolverine and the Avengers, both New and Mighty."
There will be at least a few more issues of the actual Captain America comic post-hero, the next one is said to include an autopsy. Hollywood rumblings have it we will be blessed with a movie adaption of the shield-toting soldier around 2009 that may or may not suck like Ghost Rider.
Surely the death of Captain America comes as a harsh blow to us all, but especially to those who served with him in the first Desert Storm. Cap'n Crunch mumbled on about how he once threw himself on a crunch berry to somehow save something or other. Sergeant Slaughter said he'd prepare a statement once Oprah was over. Beetle Bailey could not be reached for comment, but his remarks probably would have been hilarious 50 years ago.