DOSBox emulator port for Windows Phone. Not all DOS games are supported (due to the ARM CPU performance and hardware limitations) but a lot of good old games (including Sierras quests, Warcraft, Heroes of Might & Magic and many more) are working fine. Its also possible to run Windows 3.1 and Windows 95 on phone!
I recommend to use BT keyboard and mouse with the emulator. MOGA joystick support is coming but require some additional work (probably will work on WP8.1 only).
Hurry up: this app become paid in July! And "HAVE A NICE DOS" :)