I Fricking love my Roland MT-32, I do.

But not for the usual reasons.
(To listen to oldschool games for example)

Almost all the noise your hear, or what I like to call "my music", is produced by
by this lovely little machine.
It's connected to an old Yamaha DX21 synthesizer to which I added a
sustain pedal. A pair of cheap speakers are connected to the MT-32
and I record with the voicememo function of an iphone4.

"Ethereal Dialpad for Android" is just that: playing on one phone (galaxy s2) and recording with the other.
"Deepspace" was made on the gs2 with "Plasma Sound".

This way of recording also records background noise, such as my heater
(really prominent on Project2: "DJ Spacepiep (...)", me breathing, hammering
the keys (some are stuck) an occasional cough and birds and such. Some of them
really blend in, others less so, I admit.
On a sidenote to this, I always wondered why the audio technician recording
Glenn Gould performing the Goldberg variations got mad at him when he hummed
along; I think this humming ought to be there, it's the artists rendition of
Bach's work, isn't it?

All my music is unrehearsed, spontaneous and irreproducible. I can't read
notes and hardly ever remember which keys I pushed or what dials I turned.
(some say they can notice that)

Because of the way it's recorded, the sound is mono.
If you play it through a surround sound system it'll all come out of the
centre speaker (or at least it should) but, because it's bouncing of the
walls and coming back to you re-entering your ears you'll notice spatial
and panning effects. 
Which is rather cool.

Try moving through the room, you can amplify certain sounds or cancel out others.
Which is, again, rather cool.

Or try some of the presets of your soundsystem.
That way you don't need to move, but if you do ...

Well, on the off change of sounding extraneous, it's rather cool.