This seems like a very cool way to get to know your colleagues even better, but I do think it's limited to people in the same age range (mostly 20-somethings).
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.
