It is indeed very strange, I seem to get more clicks when non relevant ads are shown, maybe folks find ads that have nothing to do with the website subject, more interesting, because there odd or standout more then relevant ads ?
Not me.. I just yanked a bunch of yahoo ads yesterday and replaced them with adsense ads and I noticed a huge increase in clicks right away. I have no success at all with non-relevant ads myself.
an increase in clicks from adsense but big time difference in payouts.. is this the case for you also?