Kokoromi Collective has announced that Gamma 4 will be a part of next year’s GDC in March. The theme is “one-button games” and entries must only use a single button on the Xbox 360 controller. Windows and Mac OSX games are both accepted. The submission deadline is January 31st.
Also, it’s not related to Kokoromi or Gamma, but OneSwitch.org is a website dedicated to single-button games and interfaces designed for the physically-handicapped.