Something else that a 21st century mathematician should have is software for capturing presentations! See http://faculty.uml.edu/fdc/propp/propplecture_mit08.html for a captured version of the talk "Derandomized random walk in one and two dimensions" that I gave at MIT on Wednesday on my laptop. The Camtasia session-capture software suite created a video of what was on my laptop (and projected onto the screen) accompanied by an audio track of what I was saying. This talk explains some of the motivation behind the numerical cellular automaton I described in several math-fun emails with the subject line "Subject: a perplexing asymmetry" and which Steve Witham helped me explore. (Steve's applet http://www.tiac.net/~sw/2008/04/RounderRouter/ is one of the lovelier mathematical animations I've seen.) If you want to create short videos of your own, you don't need Camtasia; for segments under 5 minutes in length, you can get by with "jings" (see jing.com). I hope to create a few jings of my own after the semester ends. Jim Propp