What Exactly is Rigor in the 21st Century Classroom?

This morning, GA teacher and technology guru, Vicki Davis posted a wonderful analysis of and commentary on Tony Wagner's "Rigor Redefined" from ASCD. As always, Vicki gives us a lot to think about as we consider how we are teaching our students. I find myself constantly wondering if I'm meeting the needs my students will have by the time they enter the work world.