Depending on which sites you frequent you might come across the common internet meme the "look of disapproval". I'm on Reddit quite a bit and I see it a couple times a day.

There are times where you might want to respond with the look of disapproval, but how do you type the damn thing?

I'm a long time copy-and-paster, but I've recently took the time to figure out how to make this on my own. Not surprisingly it's fairly straight forward. Of course it differs depending on which OS you're running.

Mac OSX: Option+0CA0
Windows: ALT+3232
Ubuntu: hold Ctrl+Shift U+0CA0