From Dan Grayson:
The Macaulay2 free software project seeks one or more part-time programmers. Macaulay2 is a free software computer algebra system designed for research in mathematics and related fields. It contains its own high-level interpreted user language, and the program is written in a combination of C and C++, another language that we created to help write the interpreter that gets translated into C, and the user language. Macaulay2 depends on a number of other free software libraries.
This is a temporary position funded by an NSF contract that terminates in August, 2015, but other funding may be available after that. Applications received by Friday, November 11, 2011 will receive full consideration. […] Pay will be competitive, and will depend on experience. There are several projects available, and there will be others in the future. An applicant may be suitable for all, or for only one.
For more information, including the specific positions available and how to apply, see http://www.macaulay2.com/Jobs/.