Simple Game it is.DYK is acronym of Do You Know?.Well you have to tell the interesting fact from that is some how related to Pokémon.
So Let me start.
Do you know that Xerneas is the only Fairy Type Legendary?

Do you know that Meowth is the only Pokemon with a coin on his head?

Do you know that Clemont is the only of Ash's male friend that is not older than him.Instead they both are of same age.

Do you know that Tracey is the only character to tell his full name?

Do you know that Greninja is the fastest Water type

Did you know that Pikachu loves ketchup?

Do you know that Ash Ketchum is 10 Years old from 16 Years

Did you know that the newly 3 mysterious Pokemon discovered in X and Y are legendaries?

Not all of them.
Do you know that there is no Dark type Gym

Do you know Chimferno has gone mad of posting?

Okay Okay.You are right.
Do you know that Pyroar is the only Pokémon with base stat of 507

Do you know Sachin Tendulkar retired from cricket?

Yes.Alas!
Do you know that India has sent a space shuttle to Mars.

Do you know Misbah Ul- Haq's Tuk Tuk?

Do you know that Mega Evolution is not an evolution.