Some highlights:

- extreme gender imbalance in Qatar (probably due to migrant workers) : http://populationpyramid.net/Qatar/2010/

- Very clearly aging population in Japan : http://populationpyramid.net/Japan/2010/

- People dying quite young in Afghanistan: http://populationpyramid.net/Afghanistan/2010/

- Clear impact of WW2 in Europe in 1950 on the 20-30 age class: http://populationpyramid.net/EUROPE/1950/

The projections past 2010 are interesting too but they tend to smooth the curves which is probably not very realistic, as seen from the past. Nevertheless, it's interesting to see that the population of some countries has already started to shrink, like Russian Federation: http://populationpyramid.net/Russian+Federation/2010/