FriendlyId is the "Swiss Army bulldozer" of slugging and permalink plugins for Active Record. It lets you create pretty URLs and work with human-friendly strings as if they were numeric ids.
Some [hopefully] useful extensions to Ruby's String class. Stringex is made up of three libraries: ActsAsUrl [permalink solution with better character translation], Unidecoder [Unicode to ASCII transliteration], and StringExtensions [miscellaneous helper methods for the String class].
Configurable, but assumes a conservative strategy by default with a goal to solve many search engine index problems: multiple hostnames, inbound links with arbitrary parameters, trailing slashes.
This gem allows you to easily use [Hashids](http://hashids.org/ruby/) in your Rails app. Instead of your models using sequential numbers like 1, 2, 3, they will instead have unique short hashes like "yLA6m0oM", "5bAyD0LO", and "wz3MZ49l". The database will still use integers under the hood, so this gem can be added or removed at any time.