Also the smell of incense used to knock me out when I was kid in Church. Kneeling down. Sitting down. Standing up. Smell of incense. Hail Mary . Our Father. Tunnel vision. Feeling cold. Blackness. Wake up. Get sent home.
Of course what I have described there is fainting.
I got knocked out by a cricket bat, too. I was playing football and some other kids were playing cricket and one of the kids managed to sling shot the bat about 40 foot in the air and everyone saw it accept me because it knocked me smooth out. Woke up looking like Fernando Vargas in the Mosley fight.