One great way to contribute to the the OHRRPGCE is to simply create a game using the OHRRPGCE, that's why we're here, after all! Hopefully this wiki documentation will be helpful.
However, others want to jump in and help us, which is great as well! There's a number of different ways you can help out, from documentation, to bug fixing, suggestions, all the way up to feature development! But, it all boils down to a choice of: