3 Blue lights in the sky. One of them zig-zagging before it faded away..The first blue light was seen at about 22:45.It made a zig-zag-pattern and slowly faded away. My sister and her boyfriend saw this happening, so they decided to call my name. About a minute later, when I was outside, the next light appeared. Again, a small blue light, this time traveling in a straight line, and it seemed to go faster than a normal plane would travel. This one faded away quickly too. After a couple minutes the 3rd and final light appeared. My neighboor saw this too, because he asked himself why we were gazing at the clear black sky and so he went outside. This one also travelled in a straight line, again seeming to go a faster than normal airplanes would travel. After a couple of seconds the light disappeared, slowly fading away.I remained outside for a bit longer but I went back in, because nothing happened after that. I'm not saying it was an alien craft, but the zig-zag-movement and the color in particular made it a very strange event, which I've never seen before.