Rust is in great need of volunteers interested in making a dent in some of the libz blitz crates. There are a bunch of important crates that need to be polished up (like csv, mime, regex, semver, tar, threadpool, toml), but the first step for each is figuring out the the polish to be applied. This task basically amounts to comparing these API guidelines to a given crate, noting where the crate can be improved, and posting to an internals thread for feedback, then finally filing issues and posting them back here to solicit help resolving them.
Imagine the impact you can have by generating and resolving 20 issues against the toml crate!
There are more details about the process in this post. If you are interested but the process looks intimidating, feel free to email me and I can help you get started.
Sorry this doesn't fit into a one-liner for twir, but I know plenty of people 'front-run' this thread, so maybe somebody will see and be interested.