Not a spider, but a WASP flew into my room via an open window. I hate wasps, and what are they good for, exactly? Well, I have a wireless mouse and keyboard. I spot it fying a few feet in front of me, so I pick up my keyboard, wait for the perfect time and hit it.
It was a beautiful swing and connect. Kinda like a baseball bat swing. Anyway, it knocked the wasp several feet, hit my warddrobe, and fell on the floor, legs up and everything. 30 secs later, the legs started to move, I'd only just knocked it out.
Bonus!
I grabbed some loo roll and then proceeded to flush it down the toilet, along with the concious wasp.