[R] Teaching R in 40 minutes. What should be included?

[Dr Carbon]

If _you_ were asked to give a 40 minute dog and pony show about R for
a group of scientists ranging from physicists to geographers what
would you put in? These people want to know what R can do.

I'm thinking about something like:

A. Overview
B. data structures
C. arithmetic and manipulation
D. reading data
E. linear models using glm
F. graphics
G. programming
H. other tricks like rpart or time series analysis?

Thoughts? Other people must do similar things all the time. Is there a
repository of intro to R slide shows anywhere?