After a workshop people want to continue learning more. What book, course or website have you used as an introduction to R that you liked, and why do you like it?
I point my students at Alain Zuur et al (2009) A beginner's guide to R. Springer.
Very comprehensive, and based on the Authors many years of using R to teach biologists/ecologists about statistics. Lots of good examples and useful exercises. e-version freely available to students at my university. Warns students about the perils of
A bit dated -- doesn't cover RStudio at all. No mention of reproducible research concepts. No mention of ggplot or dplyr.
I like the swirl() package within R. It's great as a supplement to our workshops. Learners work directly in their native R environment, following prompts from the package software. There are a number of great lesson sets available for download. I highly recommend this package.
I found the Quick-R website best during my first year of using R: http://www.statmethods.net/. I then continued with a book by the same author: "R in Action" (link on webpage).