ThinGit is a DropBox alternative offering:

Self-contained Java-based application – just one small JAR file for every platform supporting Java SE. It’s by far the smallest application of this kind.

HTTP proxy support – the most reliable way of circumventing firewalls.

Command-line and graphical interfaces that map almost 1:1 allowing for execution in environments with or without graphical subsystem.

Ability to use your own file repository server

Version control