The last freelance project I worked on was for an oil and gas environmental consultant. The application computes greenhouse gas emissions at oil and gas wells. My client has used the application to manage submittals for over 20,000 oil and gas wells over the course of 5 years, and continues to use the application.
I designed the application with one of the leading MVC PHP frameworks, and used a combination of jquery and Backbone for the front-end. The user interface of the application was patterned after a Bootstrap template I found on wrapbootstrap.com. Here’s a few screenshots: