NSF DUE (Division of Undergraduate Education) has posted a program description for "Improving Undergraduate STEM Education" that consolidates a substantial portion of DUE's programs, while also offering a much more flexible proposal process. In fact, the program description has no restrictions on specific proposal elements, budget, or duration of proposed projects, other than that projects should advance the broad agenda of improvement of undergraduate STEM education.
The program description encourages building proposals on "fundamental research in undergraduate STEM education and prior research and development that provide theoretical and empirical justification for the proposed effort," and cites some published sources as possible references.
The full proposal target date is February 4, 2014. While proposals may be submitted at any time, submissions received by that date will be reviewed in the current fiscal year.
It's important for the MAA community to be aware of this re-focused effort at DUE, and to use this opportunity to seek support for efforts to improve teaching and learning in undergraduate mathematics.