I know that it's normal for the laptop to heat up, but I tend to want to help keep it cool, especially in hot weather. I placed a clothes peg under the back end of it, so that it's raised at a slight diagonal from the counter top. I also have a little desk fan, sitting behind the rMBP, that is aimed downwards so that it blows air onto back of the screen as well as underneath. It "seems" to make a small difference. What DIY ideas do you use?