Probably the best Paradox experience I have had so far:
In my latest CK2 game, I have been playing as the Lord of the Seven Kingdoms of Spain for some time, and have only just recently conquered enough of the Iberian peninsula to form the Empire of Hispania. France has shown me little mercy, and we have bashed each others' teeth in repeatedly over the interior of Spain.
As my current ruler, Velaris II, I decided to get frisky with the princess of England, who was also my kinsman's wife. I gave her two sons and a daughter that he thought were his, and he gave her none. Some time after the princess's brother inherited the throne, she usurped it for herself. Now, since she was married to a kinsman in my court, the princess was also in my imperial court when she usurped the Kingdom of England. That left me with quite a
big surprise. A very big and pleasant surprise.
Later on, when my wife died of old age, I conspired to murder my lover's husband and got away with it entirely.
And the 71-year-old emperor and his 39-year-old queen lived happily ever after.The only complaint I have is that I am unable to declare her children my own. After all, they are already part of my dynasty, and now their births are legitimized by wedlock!