One of the exciting challenges I had was to create a form for contact creation. It had to be clean and minimalistic, but functional. We wanted to have a lot of fields where a user was able to export his/her contacts from a mobile device. Nowadays, all mobile OSs have about 30 fields for contacts inside. Anyway, when a user creates a contact manually, it's not required to show them all, so we decided to focus on frequently used ones only.
Through all applications, a user can hover over a contact's avatar and get instant information about it.