Hermione loved her job. She got to teach her favorite thing every day, magic. Well, not quite magic. She taught Muggle Studies at Hogwarts school of witchcraft and wizardry. After trying the elective in third year she decided that the subject needed a complete makeover. So, after she and her husband graduated, they went straight into educational training and became professors shortly after.
One day in early spring, Hermione was walking into her high-level muggle studies class to start teaching. Most professors at Hogwarts taught behind a lectern and maybe wrote on a chalkboard. Hermione preferred to have a desk in her classroom and walk around the class while teaching. Hermione walked into her classroom and dropped her books and notes onto her desk and sat down in her chair.
BEEEEEEEEEEEHHHHHH!
Hermione jumped up out of her chair while the class tried to hide their laughter. Hermione looked under her chair to see an air horn duct taped to her chair so that when she sat down it would go off. She smiled and stood up and looked at her class, who were still giggling. "Okay class, who knows what today is and why it is important to muggle culture?
One of the students raised his hand and said, "Today is April 1st also known as April Fool's day to muggles. It is a minor holiday where people go around and play harmless pranks on each other."
"Very good Ryan, five points to Slytherin. It appears that our Defense professor has decided to partake in this particular muggle custom." The class didn't even try to hide their laughter at this. "So, what do you say we have a field trip hmmm?" Hermione asked with a mischievous glint in her eye. At this the class looked at each other excitedly and nodded. "Very good, this is what we'll do..."
Harry knew it would be coming. He just didn't know when or how. He was teaching the first years about different household magical pests that they might run into and how to deal with them. He knew the time had come when he saw the faint glow of a magical shield between him and the students.
"ATTACK!" Came the cry as a figure burst through the door throwing a brightly colored object at Harry's head. There were the telltale pops of apparition as three older students appeared on the other side of Harry throwing the water balloons at Harry. A couple more students followed Hermione in through the door, all launching water balloons at their Defense professor. They continued to throw a seemingly endless supply of water balloons at the professor until he was thoroughly soaked.
Harry laughed, wiping water off of his glasses and face. "That is for my chair," Hermione said smugly. Harry just pulled into a wet hug and kissed her. The younger students either looked away or made "ewww" noises. "Oh shush," Hermione said to the students playfully. "I love you professor Potter." Harry gave her another quick kiss. "I love you too professor Potter."