NanoHttpd is a lightweight HTTP server designed for embedding in other applications. It's only one Java file, in two "flavors", one strictly Java 1.1 compatible, and one at "current" standards. It supports GET, POST, PUT, HEAD and DELETE requests, and supports file uploading with very small memory overhead. Temp file usage and the threading model are easily customized.
wger Workout Manager is a Web application that can manage your workouts, group them into schedules (A>B>C), and print them as PDFs. It helps you keep a log of the weights lifted in the different exercises as well as your own body weight and can also create and manage your diet plans.
Playtomic is a set of client and server APIs for game leaderboards, user generated content, and dynamic updates. It began as a hosted service providing tools and analytics for game developers, but is now available for developers to operate on their own. It includes the API server which is written in NodeJS and backed with MongoDB, along with game client APIs for HTML5, Flash, iOS, Android, Windows, and Unity3d games.
EC2Dream Fogviz is a visual tool for building and managing cloud servers. It combines Fog, Ruby, and Chef into a tool that is particularly helpful when developing and testing Chef automation scripts. It currently supports Amazon AWS, Eucalyptus Cloud, and CloudStack including VPC, autoscaling, and the ability to list most entities., and Openstack clouds: Rackspace, HP Cloud, and CloudFoundry Open Platform.
PerlShare is a DropBox drop-in to create your own private file sharing "cloud". It consists of two parts; a client and a server. The server part lets you configure a Linux machine to accept PerlShare clients. PerlShare behaves a lot like DropBox. On collisions, for example, it creates conflicted copies. The workhorse for synchronization is Unison, a very reliable piece of software from Pascal Bach.