Question

I have a list, ul or ol, with n list items (lis), how can I convert this list into a two independent column list items by just using CSS & html?

Answer 1

You can do that by floating the lis, and forcing them to have a width of 50%:

ul {
    overflow: hidden;
}
ul li {
    width: 50%;
    float: left;
}

Try it here: http://jsfiddle.net/KzCxh/