So I was looking out the window to see if there was still any danger of electrical storms, as they've been going on to the east of here all afternoon. Then I notice a strange green light moving about off in the distance between the trees! At first I thought it was a meteor, but it didn't move in a straight line. Rather, it repeatedly swooped down and looped back up.
I ran into the other room to grab a pair of binoculars and a diffraction grating. I thought maybe someone was playing with a green laser pointer, although the motion seemed a bit too smooth to be guided by a human hand. In any case, that theory was disproven when I put the diffraction grating up to the eyepiece of the binoculars: this light was emitting a band spectrum, not a single wavelength like a laser does.
As I strained to glimpse the appearance of this fast moving object in the dark, I was able to vaguely make out that the light itself was elongated vertically, and that it was part of a myserious dark shape - maybe a cylinder tilted at an angle, or possibly even triangular! Slowly, as I watched it, it dawned on me what this object really is. I know exactly what is shaped like that, what moves in that fashion...
A kite. Someone decided they wanted to fly a kite in the wind, and since it was night time they attached one of those chemiluminescent glow sticks in order to be able to see it. :P