Here’s how I did it in 3 easy steps:
(1) Set up a form in Google Docs/Drive.
(2) Choose “Actions” and “Embed in Website” to get the URL for the iframe and put it in a post, like below. Then, go to the spreadsheet view of the form on Google Docs/Drive and set the share option to “everyone with the link” or “public” and copy the document key from this URL: https://docs.google.com/spreadsheet/ccc?key=0AmwAunwURQNsdFplUTBZUTRLREtLUDhabGxBMHBRWmc
(3) Make a report with knitr in R using the responses that were put to a spreadsheet at Google Docs/Drive. Do (knit) something like THIS to produce a markdown-file, i.e. (I pushed the md-file to Github for publishing – see it rendered to HTML HERE)..