Tempting as it might be (and I'm sure you're joking), don't. There was a case about this and the employee whose ears were permanently damaged won the lawsuit.
Upon answer there was no human presence on the other side.
When I spoke, I then heard a recorded voice that said "goodbye" and it disconnected.
At the worst it's either crooks making a B&E/home invasion list or worse they are collecting working number to downsell to telemarketers.
However, my Elastix PBX let's allows me banish any caller to digital purgatory by pressing only one button.
-Washington State