I know someone posted in this topic recently. Just got an invite through to "adsense optimisation day" in dublin. link: http://bit.ly/o5Zzi3
There was one recently in Oxford, UK - not been to one, but had a rep call to provide optimisation tips.
Once I'd had a rant at them about Google's complete lack of support - Google like talking at people, but despise having to talk with people - the rep actually provided some useful tips.
We used to get the reps "sorry, adsense account managers" call. Not sure whether we dropped below the threshold, as we're also trying to be less adsense reliant, or they just got bored of me ignoring their advice. Haven't heard from them in a very long time now though.