Short list of what he suggested are:

Have toys at your desk. Do things backwards. Get outside. Wear a funny hat or outfit. Reward with fun. Compete. Laugh and joke Build friendships at work. Play a practical joke on your coworkers. Make a mental game out of your tasks. Choose an attitude towards work that promotes fun.

I usually spend 20 minutes and playing pool or video games with my coworkers at lunch time, or else I have lunch with others. It is great way to recharge for the rest of the day. Read through his detail suggestions. They are great tips. The Power of Play at Work – [To-Done]