I have 2 favorites.
My first and move favorite knife kill was during a yearly newbie camp that is held in Sask.
My squad was tasked to defend a small slope covered in heavy brush. All we had to do was give them a little bit of resistance and then retreat. I had elected to get up close and personal so I went down and hid in the area that I knew that the enemy would be taking up position in and firing upon us from. I laid down next to a sizable pile of logs and stayed perfectly still. The assaulting group had moved in and taken up positions everywhere around me and had commenced firing upon my squad mates. I had formulated in my mind exactly what I could do in regards to taking down as many as possible however we were told to only provide minimal resistance. There was one player who I will not name, situated on the other side of the small log pile where I was hiding, shooting away at my squad. Eventually I sat up and poked him with my rubber knife. The look on his face to this day still warms my black heart.
My second favorite is that we were tasked to defend a small area again, an we were being confronted from the north and east sides. I dropped my entire kit minus my knife and an m9 with 5 rounds. Ran down to small wall to the south where we were taking fire from two people in the bush to the east. Leaped over the wall and used it as cover till I could move to a position where I could shoot. Popped up shot them both shooters to the east, flanked 6 or 7 man assault group that was attacking us from the north. Went to fire my pistol and realized that I had expended the only 5 shots I had taking out the first two. So I knifed them all and was then friendly fired by my own team.
"Its only a little bit on fire"