Putting in the surround sound was a bit of a pain. Like most mid-century homes, ours isn't pre-wired for modern-day technology. But the last owner must have also been a bit of a tech-head because the place is wired for cable (both TV and Internet), surround sound, etc. But the wires aren't in the walls - they run in the attic or under the house.
It's a bit ingenious because every room in the house is wired for cable and both the living room and study have Ethernet cords in multiple spots - and no walls had to be punched out to hook it up.
For the surround sound speakers, the wires run both in the attic and under the house. So it was a day of running up into the attic and crawling down under the house. It was a mixture of dirty and hot, but things are completely hooked up and everything sounds great.