Puzzling with pals can be a lark, which I suppose may be why escape rooms are all the rage nowadays. Personally, I believe it's people expressing subconscious desire to be trapped away from everything forever in a box in space/the future/a zombie apocalypse, but I'm no Dr. Ruth. Perhaps you'd like to join a buddy in an abandoned castle for a spot of thunking in free co-op first-person puzzler We Were Here [official site]. Separated in different parts of the castle but keeping in contact with walkie-talkies, pairs must pool their clues and get puzz-puzz-puzzling.
So! You and your chum find yourselves in a castle in an icy wasteland, one full of cryptic clues. One player is the 'Librarian', stuck in one small area, while the 'Explorer' roams around the rest. You have in-game walkie-talkies to chat with each other, mind, which will surely be helpful as it turns out the solutions to puzzles rely upon information the other player sees. I predict a whole lot of fun as players try to describe mystic symbols to each other.
I'm reminded vaguely of Terry Cavanagh's At A Distance, a co-op puzzler which Jim and Alec stumbled through in 2011.
You can download We Were Here free from Steam for Windows and Mac. I suppose you could also download it then refuse to solve puzzles, instead sitting at your screens talking to each other until you die then your characters live on and on until Scottish Power cut off your electricity. That's what you want, isn't it?