inFMPMD plays OVI, OPI, OZI, M, M2 and MZ (NEC-PC98) music!
The PC98 is an old Japanese try at making a common standard for computers it seems.
Lots of.. ehm, interesting games for grown ups was released for it among others.

http://www.purose.net/befis/download/lib/inpmd/infmpmd141.zip
/spot