NOAA publishes an amazing trove of historical weather data from stations all over the world – http://www.ncdc.noaa.gov/cgi-bin/res40.pl – but in a rather awkward format: each year is a separate folder, in which each station is one file, identified by two arbitrary ref numbers. Each file is gzipped text in a rather non-standard format with some inconvenient features like NULL tokens varying per field, and numbers being concatenated together with flags that give interpretation information: ftp://ftp.ncdc.noaa.gov/pub/data/gsod/readme.txt
This script lets the user specify a station and a number of years to download. It then iterates through, downloading enough years, parsing them into a much more standard CSV format read for use in (e.g.) Excel or Tableau, and concatenating them into one continuous file per station.
Here’s an example of what you can make with the output: http://eldan.co.uk/2012/10/rain-redux/