The Changemakers Innovation Awards for How to Provide Affordable Housing 

 The competition is open to all types of organizations (charitable organizations, private companies, or public entities) from all countries.

The winners will best meet the following criteria:

Innovation: The initiative introduces novel elements—in the type of housing products/services provided, in the financing mechanism, for example—that contribute to providing housing for low-income and marginalized populations. It is based on leveraged points of intervention.
Impact: The initiative addresses a major roadblock to finding housing for low-income and marginalized populations and has the potential to benefit a significant number of people not only in the location of origin but also at the country, regional, or global level.
Strategy: There is a well-designed operational model to implement the initiative and reach out to beneficiaries. Additionally, there is a solid plan to expand or replicate the model beyond current beneficiary groups/ locations.
Sustainability: The initiative has demonstrated a cost-effective approach to provide housing solutions. There is a strong funding base and a strategy to sustain it financially over the long-term
Online competition submissions are accepted until August 23, 2006. The Changemakers Innovation Award will include a cash prize of US$5,000 for the top three winners

Source: http://www.socialedge.org/features/opportunities/archive/2006/06/27/changemakers-innovation-awards  

 also http://www.changemakers.net/en-us/competitions