SQLite has always amazed me with what open source (public domain, specifically) can achieve. Absolutely amazing how much influence this one project has had.
I really need to write a script that resubmits this link on some sort of exponential backoff schedule; it's a reliable fountain of karma.
I suppose it could also resubmit old posts from silver-circle bloggers (JacquesM, Yegge et al) and from various comp sci classics -- picking random essays out of the E.W. Dijkstra archive, for instance.
And I guess I could fold in my old idea for "karma arbitrage" -- resubmitting here anything rising on /r/TrueReddit and vice versa.
"Heresy! Great evil!" I already hear you cry. And yet the invisible hand forms a pointy finger on all these things; what am I doing except to most efficiently recycle all the things that HN holds dearest, thus freeing up eyeballs for novelty?
RiderOfGiraffes tried that (with jacquesm's posts); the results were as you described. (I was a great fan of RoG's attempts to make HN more efficient, but...)
There is also a 3 year old discussion: http://news.ycombinator.com/item?id=633151