I am surprised I missed this. JenSense reported on this Wordpress plugin that makes your AdSense ads more attractive, hence noticeable, hence clickable back on June 27, 2006. She explains that it is not clear if the plugin would be in accordance or not with the AdSense TOS, so it is best to ask Google prior to placing them on your site. Below is a static image of what the plugin does from the plugin page itself at supriyadisw.

Yes, those are really beautiful.
There is an older and now newer thread at DigitalPoint Forums on the topic. Again, I would show the ads to a representative at Google, to get written permission. If they don't give it to you, then, I don't know. It is clear that the images, IMO, are separated enough from the ads - but who knows.

Comments:
Cary
08/31/2006 03:25 pm
Thanks for pointing out the plugin, looks like something to experiment with :) Just an FYI though, the link you posted to JenSense, and also the older discussion at DigitalPoint, have nothing to do with this plugin – they're about Google adding their own images to some of their skyscrapers.
Barry Schwartz
08/31/2006 03:39 pm
They actually have references to that plugin.
Jonathan
09/18/2007 03:26 pm
Looking back, this is definitely something that is frowned upon now -- it was good while it lasted, at least.