If you haven't already, check out OpenIDEO:
To become a place where good ideas gain momentum, OpenIDEO depends on participation — your inspirations, his comments, her concepts, our design process. It's these efforts, these big and small moments of sharing and collaboration, that make this platform a dynamic resource for tackling significant global challenges.
The challenge I participated in is now complete and ten final ideas were selected that the partners will seek to implement.
You can download the challenge catalogue to see the 40 shortlisted ideas that emerged during the Affordable Learning Tools and Services Challenge. You also get bonus worksheets that can help you apply a similar process to your own work.