Why count sheep?

Maybe because sheeps look like clouds which relaxes people? Okay, I'm fishing, I don't actually know the reason. I do find clouds relaxing though and on the days when I'm feeling bored enough to want to sleep (like during classes for example -cough-), I always focus on the clouds outside the high windows of my school. There's something about white, fluffy, marshmallow-y clouds slowly drifting by that makes me think of sleep. And this is not actually the answer to your question but, yeah. I think it's because sheeps look like clouds which induces sleep (if only on a personal level, hehe)

It actually depends on your favorite animal, but still sheep have became more popular as dogs bark loudly, horses are believed to be hyper-active and frogs are really annoying. So sheeps, who are peaceful and calm are taken as the unit. I have tried that method but hardly experienced any sleep. I usually listen to music on my Sony digital Walkman when I am not feeling sleepy. Another thing is to take your fantasy to a place where you always wanted to go, and it will help you fall asleep. If not, then go on a romantic virtual date with your current girlfriend, ex-girlfriend, or y-girlfriend (the future girlfriend). It helps a lot, trust me. Even if that doesn't help, then there is always Internet and myLot. Happy myLotting.

I don't know why it is sheep in particular but it helps if you count gently moving objects or animals. You are right, counting horses or dogs would probably give you the same effect, but those usually move fast or run. I think the monotomy of counting also numbs your brain and lessens the stress you are under. In any case counting sheep has worked for me.