sif (Safe Interpreted Forth)
sif is a little safe forth (safe, meaning it will never segfault etc no matter how bad your forth code is.) It's written in C and has a very cool awk script to make dictionary entries that makes it very easy to add core words in C. If you are thinking of writing a forth in C I recommend you take a look at the awk script.
STATUS: working. This hasn't been tested much, but it works. It needs a lot more words to be defined. Nobody is working on this project.
tarball: http://jasonwoof.com/downloads/sif-0.5.tar.bz2