Ask HN: What's your favorite language comment convention?

The two most prevalent conventions are by far C style with forward slashes, and using # to comment out single lines (python, and often in config files). Some languages have their own differing conventions, e.g. HTML with <!-- -->, % in matlab, ; in NASM and other assembly languages, etc.

Working with multiple languages frequently now I often mix them up. Do you have any comment syntax preferences?