Preface: i've seen these triangle-shaped vehicles many times now and viewed thru 10x50 power binoculars; so many in fact i don't bother reporting them anymore. the only reason i'm reason i am in this instance is the incredible acceleration i witnessed tonight was a first. generally, they just mozy by at more-or-less the same apparent size as commercial aircraft, but generally lower in altitude (20k-30k feet i would guess), somewhat slower (maybe 15%-20%) and absolutely no jet-engine sound associated with them regardless of relative distance. they all look the same: three solid white lights at each of the three corners and a solid red strobe light at the center of the fuselage. with binoculars and enough backlight sometimes you can also make out the outlines of the vehicle ie., solid lines connecting all the vertices. the strobe illuminates the hull just enough to differentiate the shape as well. tonight i noticed what looked like a dull-brown orb moving in the western sky - moving north-to-south - about 15 degrees off the horizon. i grabbed my binocs and took a look and sure enough it was a 3-pointed triangle. i watched it drift by for about 4-5 minutes with nothing too exciting happening, per usual - but as it got almost directly south of me (still watching in the binoculars), it literally shot almost straight up into the sky! it's appearance went from three distinguishable white lights, to a point of light, getting smaller-and-smaller as it ascended, to just gone, in under 5 seconds. it was less than 15 degrees off the horizon, having traveled considerably further away, and shot up in at least a 45 deg arc to maybe 25-30 degrees, and then simply vanished. it was easily the fastest thing i've ever seen in the sky, save for a shooting star. there was no change in light intensity, or any flash or sound; just moving at a constant speed/direction then abruptly swooping up and gone in just a few seconds; 5 seconds is being generous in all reality - probably more like 3 seconds. unbelievable to see. it was obvious that it went out of the atmosphere and not below the horizon. it simply got smaller and smaller until it was no longer visible. it wasn't in the "blink-of-an-eye" fast, but nearly that fast. must be some crazy ride flying those things.