I was thinking the other day that I would like to open-source all my random projects or startup files if I die but I couldn't think of a good way to do it.

I guess maybe a private repo with instructions could do, but it requires a technical person in the family or friends to check it if/when GH gives them access. The way that Facebook does it with their memorial service is not bad. You can set what happens with the account and repos if a death cert is received.