Via r/Design: Simple, Easy Mockups

Ikea picture frame, printout of your template, dry (or even better, wet!) erase marker.

As efficient as it is to just sketch on your iPad or whatever I still feel there's still too much latency in the task: there's still a more direct mind-to-execution link drawing freehand, on paper or glass. The distribution convenience of the digital interface isn't a problem; it only takes a second to digitize the sketch with a camera phone.

The post is here. Cool.