SalaFácil (EasyRoom) is a easy way to request a room at your organization instead of using Outlook.
There is a client and a server side. Client side is built as HTML/JS/CSS, but can be converted to a mobile application using PhoneGap. Server side is built on C# as an Exchange Web Service.
SalaFacil is licensed under BSD 3-Clause License (http://opensource.org/licenses/BSD-3-Clause)