Play while working

Play while you work is a fun idea of Fish philosophy. I feel it makes your work place a fun place to be in. Spending 8 hours at work daily is not a joke and could get tiring as well as frustrating if its just serious work work and work! The place I work in is a financial institution in one of the developing countries where work mostly means being serious. We have almost 250 employees which is a pretty big famiy. However we make sure we find time for fun things like fun quizes once a month, a movie show at times and also manage to celebrate small occasions. This seems to bring in a feeling of togetherness and 'one family' in the organisation.
Would like you guys to share how you have fun at your work place.