Run all examples of a package

Get all the base and recommended packages:
installed.packages(priority = c("base","recommended"))

A list of the functions in a package can easily be created by:
ls(pos = "package:MASS")

Run the examples for the first 10 functions of the package MASS:
for( x in paste("example(`", ls(pos="package:MASS")[1:10],"`)", sep="")){
  eval(parse(text=x))
}