Crop, canvass, resize images

Code this ourselves. ( rmagick )

Ultrasphinx

To add search engine to your site ( plugin )

Sorting using Ajax

( ajax )

Shopping Cart system

that handles reservation of items before payment, merging cart items before login with previously saved cart items, etc ( cart, checkout )

Beast forum

( 3rdparty )

Integrating checkout with Orderwave

www.orderwave.com ( checkout )

Loading fixtures to tables with foreign key restrictions

( customization, database )

Multiple image uploads

( upload )

Multiple sites on one Rails app

With multiple views too of course ( customization )

Integrating with InternationalCheckout

http://www.internationalcheckout.com ( checkout )

Cache Ajax result on user's computer

The second time the Ajax is called, it doesnt hit webserver! ( ajax, cache )

Being a REST client

( REST )

Create an RSS feed

( feed )

Persisting selected checkboxes

Let's say there are checkboxes on page1. Check some of them. Go to page2, check more, and SAVE. We can still get to know what's checked on page1 ( ajax, session )

ActiveMerchant

Using ActiveMerchant plugin to provide Credit Card form within the site ( plugin, checkout )

Drag and Drop game

Look at this: Demo drag & drop game ( javascript )

Code that cares about timezone

using tzinfo gem ( gem )

Extending Ruby class

adding new methods to original Ruby classes like Time, Integer, and String ( customization )

Implement a REST server

( REST )

Being a SOAP client

( soap )