Dapplegrey is a frontend for the MacOS X DOSBox port (which you can get from http://www.dosbox.com/ ) written in REALbasic.
With Dapplegrey you can easily set options the DOSBox gives to you w/o having to enter them manually using the Terminal or have to edit the DOSBox config file. This file will be written before Dapplegrey tells DOSbox to start.
The name Dapplegrey comes from the german word Apfelschimmel which originally means a white horse, ambiguous with the meaning of a rotten apple.