OK, while I really like Witness to the Calamity (i.e. either The Great Doubling or any of the times things got completely and utterly screwed up by bugs etc)... titles aren't any good if they have to be explained to people. I have to go with Beta Tester.
I don't play this particular card often these days but I used to be a moderator elsewhere. Only some time after I rose to that position, all the worthwhile titles for people were changed. Admin/Owner -> Chancellor is one thing, but we became... Chambermaids. True story. Besides being demoralizing, it doesn't really specify that we have the power to ban people. Its confusing. Even if it was just a massive inside joke.
Just saying. I like plain speak sometimes.