Hang Ups?

Every day this week when I've come home from work, the phone's answering machine function has had recordings of two or three hang ups. I've of course had answering machine recordings of hang ups before, but never anything like this!

And on top of that, I've had calls come in the last couple days shortly after I've come home and nobody was (apparently) at the other end each time.

I'll admit this is starting to get creepy. If the recordings of hang ups continue today, I'm seriously thinking I'll call SBC to inquire about what may be going on.