I've been at 10gen, the MongoDB company, for about 5 months now. In that time I've been writing a few new C libraries for them (and some occasional assembler).
Today I tagged libbson 0.2.0, the first release of a new high-performance C library for generating and manipulating BSON documents. You can learn more about BSON at http://bsonspec.org. BSON is the format we use to store documents inside of MongoDB. Additionally, all MongoDB drivers "speak" BSON, even if you work with a hashtable or dictionary in your language of choice.
The longer term goal is to use this as a base for high-performance C extensions to higher level languages like Python, Ruby, PHP, and such.
It has been a fun challenge building a C library that is portable but also cannot rely on external libraries. I feel like a majority of the last few months have been spent on recreating the wheel, meaning GLib. We are so lucky to have GLib in our community. It solves so many problems you never knew about.
-- Christian Hergert 2013-08-23