This is only in Gaming and meta.Gaming; I can't reproduce this on any other StackExchange site. This is on IE7.
First, the notification bar does not push the header downwards with the entire page as it does on other sites: http://imgur.com/sn3Us.png
Second, clicking anything in the header (for example, the logo), brings the header down to its correct position: http://imgur.com/Zx4bm.png
Third, this is probably just a side effect of whatever issue it is, but if you scroll down while closing the notification bar, it gets a little screwy: http://imgur.com/FKSTn.png