In the last company I worked at, when a project was major enough (read, long-running and full of tricky details) to require two devs' full-time attention, they'd hole up in a flex room for weeks at a time.[0] "The cave" basically became their temporary office until they'd re-emerge ~a month later.

I spent a few weeks in the cave and it was surprisingly chill, not nearly as oppressive as it sounds. (Although, I was much more energetic a decade ago and maybe it wouldn't be quite as fun these days :-P.) I still have a picture of my madness-induced, Git hook–infested scribblings....

[0] The team's usual room was an open floor plan, which was fine with good headphones, but naturally that solution doesn't work for pair programming.