I am looking for mathematical research opportunities, similar to the REU's in math, that are available for students that have already completed a bachelor's degree in Mathematics, but have not yet applied to a graduate program. I am not exactly looking for advice, but rather a list of research programs that will accept students who have already graduated.
I am attempting to strengthen my graduate application as well as get a taste of what it would be like to work in the field, but it seems that most everything is for undergraduates only (that have not completed a degree).
Edit: For clarification, I am a US citizen, and completed my bachelor's degree a few years ago. I have been working in industry as a government contractor (doing data analysis and math modeling type work) since graduation. I am, however, more interested in pure mathematics and I would like the pursue research opportunities in that area.