New dress code: Might be a dress up day or a dress down day or maybe a crazy hat day. Go with your imagination!
A talent show: There are various hidden talents among employees which we are rarely aware of. Try to bring these talents out!!
A karaoke afternoon: This is going to be a fun event where everybody would enjoy while singing their heart out!! Guaranteed to create a lot of laughter.
Game: We all love to play games!! Add some interesting indoor and outdoor games for your employees to cherish. Games build team spirit and sportsmanship and helps in fighting stress.
Source: http://www.truworthwellness.com/blog/fun-at-workplace.html