If we could reproduce it we'd know what's wrong, and if it can be solved with the access to admins have. I don't think that's the intended result, at the very least the CSS that positions it is wrong.
Weird that it appears only sometimes, I just opened IE and it didn't show up.
I took a cursory look only, but I think this is it:
Code:
<div id="right">
<div style="float: left;">
<div class="block block-game" id="block-game-11">
<h2 class="title"></h2>
<div class="content">
<div style="margin-top: 10px; float: left;">
<script type="text/javascript"><!--
google_ad_client = "pub-5862367125203386";
google_ad_width = 180;
google_ad_height = 150;
google_ad_format = "180x150_as";
google_ad_type = "text";
//2007-11-19: Abandonia.com
google_ad_channel = "5826423698";
google_color_border = "CC0000";
google_color_bg = "FFFFFF";
google_color_link = "0000FF";
google_color_text = "000000";
google_color_url = "008000";
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</div></div>
</div>
</div>
</div>
I don't see any ad though.
Didn't check the CSS yet. Could it be edited anyway? I don't even know where that bigass ad might be _intended_ to be; the only place where it wouldn't cover something would be at the rock bottom of the page, below the quick reply form.