X-post) http://www.reddit.com/r/AskHistorians/comments/2krnv8/whatistheoldestjokewehaveonrecord/
My record is 21 years.
Reposting an old joke that wasn't funny the first time. What gets you an upvote? Posting an original joke, or a funny joke I've heard before. What get's you 5 upvotes? Being
You know they are going to keep coming back, and despite the fact they are weaker each time, you still don't look forward to them.