Ok, so I've had a few 'spooky' experiences in my life before, but this is the first time it's happened with someone else with me witnessing the same thing at the same time.
My DS and I were about to play a board game, and I said something to him like "Shall we start then?". Then we both heard a voice across the room say "Uh-huh".
It clearly came from across the room, but we both heard it so clearly that I thought maybe it had to have been him, and he thought maybe it was me (eg somehow 'throwing' our voices)... but we both agreed it had come from the middle of the room, near his gaming chair, and both confirmed that it wasn't either of us.
I quickly got up and looked at the chair - my phone was on there, but the screen wasn't lit up like it would be if it was in use or had a new message. His gaming device was completely shut down too. No other devices were in the room.
We got on with the game and nothing else happened. I concealed how freaked out I was, as I didn't want him to be too freaked. He agreed that it was really odd, but said he wasn't scared and he said "oh I sometimes hear weird noises in here".
So I'm glad he's not scared, but still I'm not going to bring it up with him again for long time just in case it causes him to feel spooked, as personally I grew up in a house that felt haunted and I didn't like that!
I feel a bit gutted that it happened, as our home is new-build and I've never felt any spookiness here before, so I had thought it would be ghost-free!
Despite me believing in the paranormal (as my previous spooky experiences have felt so real), I do try to keep an open mind as to how there might be a rational explanation for things, or even just someone's own brain causing a hallucination - but how could that explain 2 people both hearing the same unexplained voice? If anyone has any thought, do let me know please.