Actually, on a more serious note, I've gotten some nice echo-y sounds from placing the mic next to my staircase. However, I've only done that with vocals (from what I remember...). Not sure how it would be with an acoustic guitar, although it might be something to consider.

Although, talking about running water (eh, it's somewhat relatable), I remember once I accidentilly recorded something when it started raining outside (I usually don't record when it rains because I record next to a window, just wasn't paying attention at the time, in the zone I suppose). Heard the rain in the background when I played the track back (was especially metallic-sounding because it was hitting the outside part of an ac/heating unit), was really ticked for about two minutes, until I realized it actually sounded good with the song. Even changed a line or two in the lyrics to talk about the rain. (It was kind of a off-the-cuff song about being stuck at a stop light anyway, so the lyrics about rain was fairly easy to incorporate).

I guess the point of the last one too is that some of the strangest little screw-ups can turn out to be pretty cool.