As far as casual games go (or any development project in general), the most difficult task is coming up with a core concept.  Traditionally developers have emphasized brainstorming as the most effective design philosophy, but leave it to academia to present a different answer.

Annakaisa Kultima is a researcher with the University of Tampere, and they are exploring new techniques for enhancing the creative work of games development. 

In case you didn’t know, designing fun interactive experiences is hard work.  So to help, the University of Tampere (through collaboration with the Laboratory of Hypermedia and Game Research Lab) has helped develop the GameSpace project – a group that studies the design and evaluation methods for casual multiplayer games. 

The GameSpace project has developed a series of workshops that are designed to cultivate ideas for early phases of game production.  Ironically, a lot of these workshops are modeled after games themselves (how meta, indeed) and they have generated interesting results using a small test group.

For more details check out Annakaisa's blog for a truly unique approach to game design.