Universal Design for Learning (CAST, 2011) was inspired by Universal Design in architecture.  If you design for people with disabilities before you built the house, it can be more accessible, less expensive, and more beautiful.  UDL applies that theory to learning.  Beginning with the premise that variability is what all learners share, curriculum should be designed to work for the widest variety of learners possible.  Instead of designing one-size-fits-all curriculum and then adapting it to fit the individual differences in the classroom, we should design more flexible curriculum.  Technology is a big factor in flexible classrooms, but not the only one.

A fantastic new resource is the free online book written by Anne Meyer, David Rose and David Gordon.  If you log in, you have access to this multimedia book with video, photos, and lots of extras.  In true UDL form, the book aims to move away from print only resources, changing the experience of reading for everyone, and making books less disabling.

Here is a piece I wrote with Despina Stylianou in Mathematics Teaching in the Middle School in which we combine cognitive demand with UDL.