For NoSQL fans, MongoDB is definitely the most popular solution with the simplicity and cross-platform support offered. In order to manage MongoDB databases easily, Genghis, a single-file, self-hosted and web-based solution is pretty handy.
It can be installed either as a Ruby gem or as a standalone PHP script. Genghis is capable of managing any number of databases on any number of servers with support for managing databases, collections and documents.
The interface of the application is responsive and works well down to mobile.
Requirements: PHP or Ruby on Rails