As of February (the exact date will be communicated in January), you will be able to submit your proposals anytime throughout the year via the new e-COST online submission tool. The COST Open Call will continue having the spring and autumn Collection Dates, when all submitted proposals are gathered and evaluated.
The first Collection Date will be 24 March 2015 at 12 noon (CET).
The Call is open to ideas in all fields of Science and Technology. Proposals must include researchers from at least five COST Member Countries or Cooperating State.
More info at: http://www.cost.eu/participate/open_call