Seafile is a file synchronization and collaboration platform. It comes with Dropbox-like file syncing, but is designed to be better suited to teamwork. You can build a file syncing and collaboration service for your team on your servers. It can also be used to build your own Dropbox for personal use.
Megatools is a collection of programs for accessing the Mega service from the commandline of your desktop or server. It allows you to copy individual files as well as entire directory trees to and from the cloud. You can also perform streaming downloads (for example, to preview videos and audio files) without needing to download the entire file. The tools are robust and optimized for fast operation, as fast as the Mega servers allow. Memory requirements and CPU utilization are kept at minimum. You can register an account using a "megareg" tool, with the benefit of having true control of your encryption keys.