At company I co-own, by coincidence started also with my childhood friends, we are having tremendous success with just packing the computers, whiteboards and going somewhere together as a team, for example to mountains.
Spend half a day on ferrate, then cook together lunch and the rest of the day work. It boosts the productivity, team feeling, happiness and brings new, fresh ideas. We try to do it every 2–3 months, different place, different topic, different fun. And it works.