What are the most interesting / unusual design elements used on websites that you have seen?
<p>I am leading a team to build a website for a client. The client is a company producing games, toys and widgets. They have specifically asked for at least 2 design features on the site which are intelligent, interesting and unusual! (I am quoting the specs I got)</p>

<p>Further, they do not want any Flash - loads of JS are OK though.</p>

<p>I thought I would ask the SO community for their opinion. So, what are some of the most interesting / unusual design elements that you have seen or used yourself?</p>
