After searching and waiting for timidity and reading the tip from the user Matan, i've got MIDI working

Here it goes:

Ctrl + Shift + X (open terminal)

1) sudo gainroot
2) apt-get install wildmidi
3) apt-get install freepats (18mb or so with instruments)
4) edit "/usr/share/applications/defaults.list" with your favorite editor and put "audio/midi" and "audio/mid" on the "Media Player MIME Types" list (just copy any line, change the mime)

Done

Now just open the MIDI files with file manager.