1. Json builderRails provides an excellent XML Builder by default to build RSS and ATOM feeds, but nothing to help you build complex and custom JSON data structures. JSON Builder is here to help.
3. ItunesA Ruby wrapper around the iTunes API that lets you search for any sort of data that is available on the iTunes store.
4. Cmd EnterEvery textarea should let you submit comments by pressing cmd-enter or ctrl-enter. For every site that doesn't support it, a kitten weeps. Here's to making less kittens weep.