300x250 Expander Right
The 300x250 Expander Right ad unit (also available as a "left" expander... depending on your page layout) is designed to attract a viewers attention by expanding the standard 300x250 ad unit into any size and shape you like. Adding a partially transparent image to the expanded container can have a great effect as well (i.e - a car driving driving out of the ad "onto" the page).