Oh noes! I shall now attempt to distract the reader from my post's un-funniness by creating another equally un-amusing post, exploiting my own lack of humor! And I will follow that with a short comment about the actual topic of the thread, only large enough to make this post not spam.
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Curses! My vein attempt at mild humor has failed!
Anyway, @Aardwolf: Do you mean like actual active members? The extreme majority of the people here just pop in for like 3 posts to get their bugs fixed. IIRC there was one semi-active voice actor guy who was ~45. But if you just meant in total, I'd say Grandad, as Hades said. IIRC there was another guy in his 60s here, too.