I had a chance to participate in a phone call last week regarding the National Math & Science Initiative. This is a major undertaking to improve the quality and quantity of math and science learning opportunities around the country. It is primarily funded by the ExxonMobil Foundation (with $125 million!!!) and seems likely to serve as a pool for other funders to have a larger impact together. They plan to fund proven models, starting with two Texas-based projects, one which prepares science undergraduates to teach in public schools, and one which supports high school students in taking AP classes. RFPs are currently open to replicate these models in other states/regions.
Replicating programs that have been studied is a great way to go. Replicating at local/state-levels allows those with a closer connection to the target audience to tailor their version of the program to unique local needs. Personal experience tells me that holding all youth to high expectations works, but it also can require a lot of support beyond academics, so let's all be prepared to be involved.