The American Association of People with Disabilities (AAPD) sponsors a summer internship in Washington, DC for current college and graduate students and recent graduates with disabilities. This full-time internship will place you in Congress, a federal agency, or a national organization. Apparently (and oddly) you can even work at Walmart.
You will receive dorm housing and a living stipend (as well as excellent networking and a big plus on your resume).
More information at www.aapd.com/summer-internship-program.