I am grateful that we live in an age in which individuals like Yihui Xie make things that help others make things. Aside from his extraordinary work with knitr, I am enjoying the ability to make any kind of animation I want with his animation package. My introductory stats lectures are less boring when I can make simple graphs move:
    
 
  Correlations
  Code:
  cnt<-1000
  for (i in c(-0.9999,-0.999,seq(-0.995,0.995,0.005),0.999,0.9999,0.999,seq(0.995,-0.995,-.005),-0.999)){
  Cairo(file=paste0("S",cnt,".png"),bg="white",width=700,height=700)
  cnt<-cnt+1
  rho<-i
  plot(matrix(rep(1,2*n),nrow=n)%*%diag(m)+d%*%chol(matrix(c(1,rho,rho,1),nrow=2))%*%diag(s),pch=16,col=rgb(0,0.12,0.88,alpha=0.3),ylab="Y",xlab="X", xlim=c(40,160), ylim=c(40,160),axes=F,main=bquote(rho==.(format(round(rho,2),nsmall=2))))
  lines(c(40,160),(c(40,160)-100)*rho+100,col="firebrick2")
  axis(1)
  axis(2)
  dev.off()
  }
  ani.options(convert = shQuote('C:/Program Files/ImageMagick-6.8.8-Q16/convert.exe'),ani.width=700, ani.height=800,interval = 0.05,ani.dev="png",ani.type="png")
  im.convert("S*.png",output="SEE1.gif",extra.opts="-dispose Background",clean=T)