I had just come back from a date, and was dropping my date off at her apartment. I looked up at the sky, as I am wont to do from time to time, noticing how clear it was and how it was a perfect stargazing night. A few moments later, as I was looking around at the stars, I noticed the lights.The objects consisted of pairs of green and red point-like lights, like airplane navigation lights. However they showed no movement like an airplane, showing only a creeping eastward drift barely perceptible over the span of approximately ten minutes. My date said that she witnessed blue lights as well, but I personally do not recall seeing them, I only witnessed the red-and-green pairs of lights.I first noticed them in the northern sky, approximately two closed fist-widths (held at arm's length) north of the bowl of the Big Dipper, approximately where the constellation Draco should be. There was a swarm of several dozen of them. My first thought was that they were either a star cluster like the Pleiades, or that they were helicopters hovering at extreme altitude. However, the absolute lack of noise combined with the sheer number of them (I would estimate no fewer than 20, perhaps twice that many or more at its peak) made that seem implausible to me. The lights were blinking/pulsating, but in a manner more like the scintillating twinkling of a star rather than the periodic flash of an airplane navigation light or the steady point of light of a satellite (although the twinkling was much more pronounced than any star I have ever seen; when we first noticed them, the lights were clearly, visibly twinkling even though the area we were in (an apartment complex) was very light polluted.The objects faded with time as they very slowly moved eastward. This made me think that they could possibly just be satellites moving into the Earth's shadow, a phenomenon I had seen before with individual satellites, but they drifted much, much more slowly than any satellite I have ever witnessed. The movement was all but imperceptible except over several minutes (perhaps 7-15 minutes), whereas most satellites I have witnessed have had a readily perceptible motion against the background stars, bringing them from horizon to horizon within a few minutes. These objects moved perhaps four fist-widths (held at arm's length) across the sky from the time we spotted them until they slowly faded away. That, combined with the fact that I have no idea how a swarm of object in orbit could possibly move collectively in the manner I saw according to my (albeit amateur) understanding of orbital mechanics and my personal experience with satellite watching, left me at a loss to explain them.The size of the swarm as a whole was very large, possibly being twice the size (or more) of an open hand held at arm's length.My date and I were both eyewitnesses to this event.