This should be a very simple project. I have a project on Github which is a C-based bitset implementation for Ruby, based on Tyler's original github repo. The implementation is functionally complete, but contains an error which causes the Ruby VM to crash. Something about a freeing a pointer which has already been freed.
The work is to identify the problem and fix it. I am imagining this would be a very simple job for an experienced C programmer.
The repository can be found on github.