Readlebee - "An attempt at a viable alternative to Goodreads."
The history and legacy of jQuery - Personally, I still think jQuery is a better choice than (insert gargantuan heap of JS dependencies of your choice here). But I'm a curmudgeon.
Internet Object - "A thin, robust, schema oriented yet insanely simple data serialization format for internet!" If JSON wasn't so popular, people wouldn't keep redesigning it.
Comby - "Comby is a tool for matching and rewriting code." This gives you flexible cross-language templating.
Zeal - "ZEAL is the programmer's scratchpad. But beyond a place scribble in code it saves all evaluations—that is code, result, and metadata—and allows the user to search for it at any point in time."