No-selectable

@mixin no-selectable() 
{
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

I think this one comes from Bootstrap, but I just came across it reading someone's code, and it is particularly useful for a project I'm working on ..