You probably already use Capistrano for your application deployments. This gem is a addon which posts events to a Google calendar on deployments and rollbacks. My company use a calendar for each project and thanks to our Continuous Integration system, Jenkins (you should use one too too), we also have the information whenever a build is successful or failing, giving us a quick overview of past deployments & build.
Combined images, also known as CSS sprites are a great way to minimize HTTP requests, and thus speed up web sites. This technique is effective but its maintenance can quickly turn into a nightmare if you do not have the proper tool to automatize it. The sprite-factory gem help you manage your sprites by automaticly combining them and producing the according CSS. If you’re using Rails, add the gem to your Gemfile, create the following file to your lib/tasks directory as assets_resprite, put your sprites in app/assets/images/sprites/ and then call
rake assets:resprite to obtain your assembled image and resulting CSS. You could also use Guard to automaticly update the output image whenever you add or update the sprites.
Dropbox-api & Dropbox
Dropbox is a file hosting service, which uses the cloud to store them. While I’m not a big fan of cloud based applications (I am not the only one), Dropbox has clients available on several and allows a great proximity with customers: e.g. reports export in their private dropbox directory or automatic file processing whenever they add them in a specific Dropbox directory. The company behind Dropbox also released a gem - called Dropbox -, which syntax differ slightly from Dropbox-api.
Mailcatcher is daemon acting as a SMTP server which catches any mails sent to it, and display them in a web interface like a webmail. It can also display the HTML or text alternative.
If you have to develop something on the Internet that is not static HTML, chances are that you’ll want to tell about it : new products, new posts or the latest tagged version of your opensource software. With only a few lines to configure it and one more to post a status, the Twitter gem is very easy to use and has access to all the API : direct messages, mentions, saved search, etc.
Wkhtmltopdf transforms a HTML page - and all its assets - in a PDF using the webkit renderer. Result are really impressive : see the rendered pdf for www.cnn.com. It is a nice alternative to others systems, notably those - like prawn - that give an API to manually create PDF (see this exemple).
Nice icon (colored in red) from artdesigner.lv