Recently I was researching about DHTs and developed a DHT Sniffer in Go which connects to some known DHT Routers and sniffs all the annoucements.
I've quickly added ZincSearch and it is now basically a search engine which can search for hashes, name or files contained in the torrents. It is able to index around 5-10k annoucements per second, so the index grows quite fast.
Now, I am thinking about releasing it as open-source for others to study, but not sure if I should, because it might be used for "evil".
https://github.com/boramalper/magnetico