If I went on a holiday with a buddy from work, things would not work out so good, as I am a lark and he is an owl. I like waking up at 6-6h30 and going to bed at 22. He on the other hand likes to get up at 10 and goes to bed at around midnight-2. That doesn't matter when we work together, but spending the whole day together is something else.
We also structured the days pretty well so although everyone on the team has different hours normally, they were willing to put up with a strict schedule we put together for the them during that week.