Not to say that life isn't fun at any other age, but at 5 just about anything in life is fun, or can be made fun. I love that attitude.
Even the covers off a pair of binoculars can be fun.
Really, really fun and extremely entertaining.
It is important to remember it is the little things in life that make it memorable and fun. I need to take cues from my 5 year old more often. Life is so fun!