Yesterday Microsoft posted saying that they are launching a new Mobile operating system, which is based on the MS-DOS. The phone will be working on DOS promt and users will have to type commands. There are demo of the phone also. See the video below.
At first this seems to be just an April fool joke, actually it is a prank partially. It is a Windows Phone application from Microsoft Mobile. It really work just like DOS on the PCs. You can open Camera from Programs\Phone\Camera.exe. The Camera take photos in ASCII, Black and White and CGA modes. It works on both front and back cameras.
More screenshots
The app supports Camera, Contacts, Ineternet, Email, Maps, Market, Phone Review, Search and SMS. Below you can see a click using the camera
You can find a Rock Paper Scissors game on the DOS prompt, just check Games\RPS\RPS.EXE. You may need to read the instructions to start playing the game. You can see screenshots of the game below
You can try most of the DOS commands on this applications. Personally I tried the application and loved it. If you want to try the application you can get this from the Windows Phone Store. Here is the link