ostests is a tool that allows you to create and publish interactive tests easily. The tests (or exams) support many different formats and most of the cases are intended to be auto-graded, but you can also include open questions that require the intervention of examiners.
Quenlig is a standalone system allowing the creation of interactive Web tutorials and questionnaires. The system analyzes the student textual answer, so it is perfectly adapted to create courses and practical works on Unix, Python, SQL, etc.