The caller did not dial my "normal" house or cell number, but the one assigned me by a service called "Sideline" that gives second numbers (using VOIP, I think) to cell users. They have called several times in the past couple days, and leave a blank (i.e. no speech) voicemail then hang up. Annoying, as I often sleep during daytime. I used spydialer.com to back-trace the number to them.
Was a telemarketer. He told he was calling some name. When I told it was a wrong number, he told doesn't matter, you won a 3day-2night vacation something..