http://agilewebdevelopment.com/plugins/list

这个地方有很多的RAILS插件

Acts as Authenticated
Acts As Authenticated is a simple authentication generator plugin for Ruby on Rails.
Rating: 3/5 (270 votes)
Added on 14 Apr 2006
File Column Plugin
Makes handling of file uploads really easy and has a nice integration with rmagick.
Rating: 4/5 (46 votes)
Added on 14 Apr 2006
Acts As Enumerated
Treats ActiveRecord models as an enumerations.
Rating: 5/5 (40 votes)
Added on 14 Apr 2006
Active form
Provides support for non-ActiveRecord Model Objects that support Validations.
Rating: 4/5 (20 votes)
Added on 14 Apr 2006
Acts as versioned
This library adds simple versioning to an ActiveRecord module. ActiveRecord is required.
Rating: 4/5 (21 votes)
Added on 14 Apr 2006
Acts as deque
Make your models behave as a stack, queue, or dequeue.
Rating: 4/5 (7 votes)
Added on 14 Apr 2006
Acts as ldapable
An acts-as mixin providing model to ldap mapping that gets updated during persistant operations.
Rating: 4/5 (3 votes)
Added on 14 Apr 2006
GUID
This plugin for ActiveRecord makes the "ID" field into a URL-safe GUID.
Rating: 4/5 (8 votes)
Added on 14 Apr 2006
Filters column
Use a separate column to automatically store the results of text filters like Textile or Markdown.
Rating: 4/5 (7 votes)
Added on 14 Apr 2006
Annotate models
Add a comment summarizing the current schema to the top of each ActiveRecord model source file.
Rating: 5/5 (57 votes)
Added on 14 Apr 2006
Userstamp
Adds support for automatically tagging your object�s created_by and updated_by attributes with the currently logged in user.
Rating: 5/5 (12 votes)
Added on 14 Apr 2006
Acts as habtm list
Manages ordered lists through a join-table. It is providing almost the same API as acts_as_list.
Rating: 4/5 (6 votes)
Added on 14 Apr 2006
Riff
Detect differences between two activerecords.
Rating: 4/5 (4 votes)
Added on 14 Apr 2006
Acts as ordered
Allows you to access the adjacent models in a given order. Adds next and previous accessors to model instances.
Rating: 4/5 (11 votes)
Added on 14 Apr 2006
Validates date time
Adds validators to validate dates and times entered as strings: validates_date, validates_time, and validates_date_time.
Rating: 3/5 (36 votes)