Folks,
I think I should start a new thread for this, because a similar one I saw is a bit old and the resolution there doesn't seem to apply to what I'm running into now.
Anyway, my date_select calls are bombing on me with the exception:
/Users/wgray/Documents/Sources/Rails/tempo/vendor/rails/actionpack/lib/ action_view/helpers/date_helper.rb:655 date_or_time_select.insert(0, self.send("select_#{param}", datetime, options_with_prefix(position[param], options.merge(:use_hidden => discard[param])), html_options))
(rdb:1) eval self.send("select_#{param}", datetime, options_with_prefix(position[param], options.merge(:use_hidden => discard[param])), html_options) ArgumentError Exception: wrong number of arguments (3 for 2)
I can't seem to find a way to step into, or down into select_year without the exception bubbling up on me and ending the investigation. Using step gets me to the end of otpions_with_prefix, but when I come back up, I can only seem to execute the send call, which then bombs. But anyway, my call to date_select is nothing weird, and I have no plugins over-riding its behavior:
But are their plugins overriding some other ActionView internals? Just about everytime someone has had similar problems its always turned out to be a plugin or monkey patch to some internal function.
Fred
So I went looking further, because as you say, that definitely sounds like the problem.
Aaaand D'OH! We had a monkey patch for select_year at the bottom of
application_helper.rb 
I've moved that bad boy over to initializers/date_helper.rb with our other patches and added the third html_options param, works like a charm now.
Thanks Frederick!