Aliens have invaded my computer.

[Tingalz]

This once happened to me. The aliens turned out to be pretty cool.

[Ad Bot]

[Rughugger]

This once happened to me. The aliens turned out to be pretty cool.

Thanks for the props. *slips the bribe in his mailbox*

[Miga]

Ugh, a more serious reply:
It's just your speakers picking up radio chatter, most likely from aircrafts or radio stations.
My speakers did it, my brothers speakers did it, it just stops at random one day.

[Riot]

Walky talky does that toos