I have a main content area and a right column content area. The content in the right column is usually short. 
How do i make the content from the main content area overflow into the right if there is no content there.

**CSS**

```
#left {
    width: 440px;
    float: left;
}
#right {
    margin-top: 60px;
    width: 250px;
    float: right;
    padding-left: 20px;
    border-left: 1px;
}

```