title: Too many factors on x axis
body: <p>What's the best way to deal with too many factors in a plot, assuming that the factor variable is ordered? The default doesn't look nice:</p>
  
  <pre><code>ggplot(data.frame(x=factor(trunc(runif(10000, 0, 100)), ordered=T)), aes(x=x)) +
    geom_histogram()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/evC8x.png" alt="ugly example"></p>