The Google Summer of Code has a list of accepted organizations. Next to each organization there are a bunch of tags. One can download the all the data as a csv file.
So I looked at the data and grepped it for several keywords.
Here are the results sorted by number of hits.
There are a lot of URLs in the listing that have php in them. counting php gives 45 results but apparently about 20 of those are URLs. That might also mean something.
Published on 2011-04-10 by Gabor Szabo