So, playing COD4 a few months ago I was running along the backside of Overgrown, trying to sneak up behind a sniper i had spotted in the bushes. I snuck up behind him, knifed him out, and was running back the way I came when his buddy popped out and we started trading AR fire. He was bunnyhopping around(grr), and without killing eachother we somehow exhausted our clips. SO, we starts reloading and circling eachother and just as I pull out my mag to reload he pulls out his knife, and rushes me. Freaking out, and taking what feels like forever to reload I start backpedaling frantically. Just as i realize my last mag has like 2 shots left and hes getting closer, i backpedal over a small patch of grass and I notice the "F" of "Press F to pick something up" and immediately hit it, almost out of instinct. Sure enough its my old sniper friends fully loaded Barrett .50 cal, and just as the knifer closes within a foot of me I raise the rifle and punch one right through his chest. Dead. woot! ^_^
Moreso a going-out-of-my-way story, I was playing on the same map and looking at my radar, I realized there was on orange dot standing on the other side of the tall brick wall situated in the center of the map, so i walk right up to it, face my invisible foe, look straight up and chuck a frag. I step back a bit to watch. Sure enough, (and I could tell because of the little ticks that go off when you hit someone, and watching where they were on the screen) the grenade flew straight up and over, came down and bounced off his dome, and exploded about an inch above his head. Probably my best use of a single frag, ever.
Haha sorry those were so long-winded, im in a writey mood today