We're a nonprofit building an interactive grammar tool. Quill provides students students with passages that have grammatical problems placed within them. Students proofread the passage, and then they receive a personalized lesson based on their results. http://www.quill.org.Quill is an open source project built in Rails, and we're looking to connect with developers that are interested in contributing to an open source project. https://github.com/empirical-org/quill