DOSBox is a x86 DOS emulator that can be used to run old DOS-games under OS that don’t support it like Win2k, XP, FreeBSD and Linux. Graphics and sound emulation are optimal. This free, open source, cross platform application that supports over 3,000 games also provides a quick installation from the repositories in Ubuntu with
sudo apt-get install dosbox
For how to get started, refer to this document at the Ubuntu Community.