Vodafone had problems with a 3rd-party product, which was not compliant to the HTTP/1.1 specification, especially with parameters on the URL. They wanted a shortterm solution, which could 'fix' URL's before they were send to the 3rd-party product. A URL rewriting script was written, which could proxy requests and at the same time fix the URL.
Although this was a temporary solution, it became sort of permanent.
This was a parttime project with only a couple of days effort. Because of some changes in the URL requirements of the 3rd-party product, the script had to be changed a number of times.