The Lync Server 2013 demo VM set is now available on the Microsoft Download Center. This VM set is pre-loaded with more than 200 contacts with photos, and is integrated with Exchange Server 2013 Unified Messaging (UM), SharePoint Server 2013, and a Unified Communications (UC) Development platform.
For the best experience, please take a few minutes to download and review the Quick Start Guide from the site. This will help make sure your environment is properly configure and prepare your Virtualization environment (Hyper-V)”
Note: These virtual machines are supported on Windows Server 2008 R2 and/or Windows Server 2012 OS environments. These modules are not currently supported on Windows Server 2012 R2.
A description from the Download Center:
"This download comes as a pre-configured set of VHD's. This download enables you to fully evaluate the Microsoft Lync 2013, Microsoft Exchange 2013, SharePoint 2013, and UC developer platform APIs including the Microsoft Lync 2013 SDK, the Exchange Web Services Managed API 2.0 as well as the Microsoft Lync Server 2013 SDK and the Microsoft Unified Communications Managed API 4.0. Also, Lync Server."