ggvis is a data visualization package for R which lets you:
Declaratively describe data graphics with a syntax similar in spirit to ggplot2.
Create rich interactive graphics that you can play with locally in Rstudio or in your browser.
Leverage shiny’s infrastructure to publish interactive graphics usable from any browser (either within your company or to the world).
The goal is to combine the best of R (e.g. every modelling function you can imagine) and the best of the web (everyone has a web browser). Data manipulation and transformation are done in R, and the graphics are rendered in a web browser, using Vega. For RStudio users, ggvis graphics display in a viewer panel, which is possible because RStudio is a web browser.
Histogram:
Scatterplot with smooth curve and interactive control: