I see Jon Skeet has written a function graphing sample using DLR and Silverlight. It occurred to me that it would be very easy to create something like this using my Live Geometry framework.
So here it is: http://graph.livegeometry.com. One difference is that I didn’t use DLR and Python, but wrote my own hand-written recursive descent parser for math expressions. One reason for this (except the fact that it was overdue for me to write a parser myself) is that I don’t think DLR will run on the Windows Phone 7 (since Expression.Compile() and Reflection.Emit are currently not supported on the phone). Also DLR is a bit on the heavy-side with > 1 MB increase of the .xap file.
Sources, as usual, at CodePlex.