acts_as_most_popular: Data popularity extension for Rails models
Shane Vitarana, creator of Rails Stats, has released a new plugin, acts_as_most_popular. acts_as_most_popular adds a method for each column in your model's table called most_popular_* that returns an array of the most popular entries within that column. For example, if you have 1000s of users in your user table, User.most_popular_names would return an array with the most popular names, as found in the name column.
Learn more here. This seems like the sort of thing that might eventually be useful as a Calculation of some kind.