Ask HN: could you please post any Hacker News associated sites and tools here?

There are many sites that derive content from Hacker News, including the popular, http://searchyc.com What other HN derived sites or tools do you know about or use? It'd be great to see a reference post about such derivative sites, just like the feature requests item, and that's why I am posting. This question may have been posted before as it's important for users, site developers and HN itself. By not having such a reference freely available, people may be missing out on something that'd really help.