REQUEST - Best way to find a convention at a specific hotel during specific dates?

I'm looking to book a room at the Grand Californian in Anaheim, CA (Disneyland resort hotel), but all the rooms are booked for the dates I need.

The hotel is a popular spot for corporate (and open to the public) conventions and I know they always have a number of rooms blocked off (at a cheaper rate as well). So, I want to find out what conventions will be at the hotel during the dates I'm looking to go.

I tried a simple google search for "Grand Californian convention <my dates>" and "Anaheim convention <my dates>", but couldn't find much. The hotel obviously won't knowingly give out this info so simply calling them and asking won't help (without some clever way to "convince" them into giving me the info...lol).

I'm hoping the clever folks here might have some ideas on the best ways to find out this info.

Any ideas?

Thanks in advance !!!!

Call the local Chamber of Commerce or Visitors and Convention Bureau?

Try looking up the convention center. http://www.anaheimconventioncenter.com/events.cfm