In chamber of secrets Mrs. Weasley sends Ron a howler after the car incident. Ron and Harry had only taken the car because Dobby had stopped them getting on to platform 9 3/4. Without Voldemorts existence that wouldn't have been necessary. However, I think Harry got Lily's personality more so than James', but having being raised with James and Sirius' influence, he probably would've been somewhat encouraged to be a troublemaker, so I imagine he and Ron (and Hermione by extent) would've still found themselves in a fair amount of trouble. As a result, Ron and Harry probably got more than one Howler during their years at Hogwarts. This probably takes place around their second year.
The great hall was silent as Mrs. Weasley's voice finally dissolved, Ron was sitting looking shell shocked, his face was pale at the moment, but Harry suspected it would be crimson in a very soon, once Ron processed what had happened and that everyone was staring at him. The silence didn't last long, giggles started to break out around them and then people started pointing at the ceiling.
"Oh no," Harry murmured, spotting Hedwig, another red envelope clutched in her beak. The hall once again quieted as the howler was dropped in front of Harry.
"Your turn," Ron whispered as Harry reached for it with trepidation. As soon as he'd unsealed the envelope, Lily Potter's voice filled the hall.
"HARRY JAMES POTTER, YOU SHOULD KNOW BETTER. HOW DARE YOU? IM SO EMBARRASSED. AND DRAGGING POOR RON ALONG WITH YOU. I'VE NEVER BEEN SO ANGRY. YOUR FATHER AND I ARE JUST OUTRAGED. Aren't we James?" There was a moment of silence, Lily obviously waiting for James to back her up. "Yes, very angry Harry," said James' voice, but Harry knew his dad well enough to hear the amusement in it. "JAMES," Lily shrieked, "DON'T ENCOURAGE HIM." "But it was genius," came Harry's dad's voice, an unmistakable hint of pride in it, "Did you hear how-?" "I DON'T CARE HOW. YOU SHOULD BE TEACHING YOUR SON HOW TO BEHAVE AND FOLLOW THE RULES."
Then a new voice joined Harry's bickering parents'; "HARRY JAMES POTTER I AM SO PROUD OF YOU." Harry couldn't help grin, but it faltered a second later when his mother replied, "SIRIUS BLACK, YOU STAY OUT OF THIS. THIS IS BETWEEN HARRY'S PARENTS-" "BUT IM HIS GODFATHER." "EXACTLY." "NO, ITS MY JOB TO ENCOURAGE HARRY, TELL HER PRONGS." "Sorry Padfoot, I think I'm going to stay out of this one," said James hesitantly, but Lily didn't like that. "JAMES, YOU TELL SIRIUS TO STOP ENCOURAGING HARRY, AND YOU DISCIPLINE YOUR SON." "But- but Lily-" "NO BUTS."
To Harry's relief, at that moment, the Howler started to run out, its edges beginning to smoke as it prepared to burst in to flame. Just before it did however, James and Sirius got their last words in. "WE'RE SO PROUD OF YOU," they said together, as the howler combusted.
Ron sighed jealously from next to him, "I wish my dad was as cool as yours," he said. "Mom's probably not going to speak to him for a week though," Harry said with a laugh.
There were a few chuckles around the hall from the other students as everyone went back to their breakfast, the mornings excitement over. Harry couldn't help glance up at the teachers' table.
Dumbledore was looking amused, Professor McGonagall had her head buried in her hands, obviously lamenting the fact that even though the Mauraders had graduated, they still found a way of causing trouble in Hogwarts, Snape's sneer was as pronounced as ever, a look of disgust on his face over their antics. And Professor Lupin (which is what Harry had to call him in school, but he'd always be Uncle Moony outside of it), who'd been the defence against the dark arts teacher for almost ten years now, and who still couldn't resist going along with James and Sirius' antics on a regular basis, well, his eyes were twinkling merrily and when he met Harry's gaze, he shot him a wink.
Surprisly to Harry, Fred and George were not joining in on making fun of him and Ron like those around him were, in fact they were staring at Harry with a mixture of shock and awe. "Everything okay?" Harry asked them warily, for it was rarely a good thing when pranksters stared at someone that intently.
"Harry," said Fred, the twins leaning towards him so no one else could hear them, "Did- did they say," he had to stop himself, taking a steadying breath, "Did they call themselves," George continued for him, "P-P-padfoot and P-Pr-" "Prongs?" finished George.
"Well yeah," said Harry, confused, "Those are my dad's and my godfather's nicknames."
Fred and George both gasped dramatically, "Noooo," said Fred disbelieving. "As in Moony, Wormtail, Padfoot and Prongs?" asked George.
"Yeah," Harry said again, "those are my dads and his friends' nicknames for each other."
"Wow," breathed George. "They're genius'," said Fred.
"Wait," Harry said, "How do you know their names?" and then it clicked.
Fred leaned even closer to him and whispered, "we found the map."
"Really?" Harry asked, disbelief and delight mixing through him, "My dad told me all about it, he said Filch confiscated it just before they left Hogwarts. I've tried to find it but it wasn't in his office."
George nodded. "That's because we found it in our first year."
"Wow," said Harry.
"We owe your dad and his mates a lot," Fred told him, "we wouldn't be the messers we are now if it wasnt for the Mauraders."
"But," George sighed, "I suppose we should return it to you,"
Harry squirmed uncomfortably. He wanted the map of course, he couldn't wait to tell his dad he had it, but it didn't feel right to take it from them.
"Don't worry," said Fred, obviously reading his expression, "we know it by heart now. And we can always borrow it off you if we need it."
"Deal," Harry agreed, as George slipped the map to him under the table. He couldn't wait to write to his dad and Uncle Padfoot to tell them.
He couldn't believe how a morning that had started off with two howlers had ended this fortunately.