...meant to commemorate his birthday- nothing more, nothing less.
Warnings:  Not part of AtO's timeline- just borrowing that universe. Beware of huge  plot-holes since this ignores any established plot, events and countless other things. Let's just  consider it super crack-ish, to be safe. Very un-edited.
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"I think we managed a pretty awesome haul today. Thanks for not  bailing out on me otherwise grocery shopping would have been horrid,"  Harry said as he climbed up his stairs.  
Harry turned back slightly, "Actually, you've been unnaturally nice  about helping me get groceries. So spill, what's put you in that good  and helpful mood?"
Itachi just shrugged. 
"Did Kiba's sister finally agree to go out on a date with you?"
Harry chuckled at the happy embarrassment he detected from Itachi's movements as he fished out his keys. After a slight jingle, he pushed open the door and stepped in with Itachi close behind.
"HAPPY BIRTHDAY!" A chorus of voices yelled out loud.
Harry flinched back in surprise and blinked at the numerous faces in  his decorated apartment. Streamers, balloons and other colourful items  filled every inch of free space. "Birthday? It's not my birthday."  After a fairly awkward silence, Harry gasped in surprise and turned to Itachi. "It's your birthday?"
Itachi narrowed his eyes.
Harry winced. "Of course it is, I knew that. I bet you're completely surprised with this..."
"Nii-san, you didn't know?" Naruto came forward and grabbed some of  the bags as Harry closed the door. "But you kept him away while we  decorated this place." 
"I had to buy groceries."
"So you weren't just taking him around to keep him away from here?"  Naruto said, "I thought you realized the plan when I asked if you'd be  away from here."
Harry shook his head.
"Then why were you taking him around?" Shikamaru asked. "And why'd you bring him here?"
"People  tend to lower their prices when he's around. I thought it'd be a waste not to use his skills." Harry shrugged and twitched  when everyone stared at him in blatant disbelief. "What? Well, it's not  like he knows my birthday."
"July 31st," Itachi said with a scowl and turned away placing the other bags inside.
Harry blinked in surprise. "I stand corrected."
"Nii-san!" Naruto slumped in slight embarrassment.
"What? Itachi doesn't mind, right? Itachi?" Harry turned to his  friend."Oh! This was probably another reason you were okay with all the  grocery shopping. You were expecting this party?"
Itachi didn't acknowledge him and walked away towards the other side of the room, keeping his back to Harry. Everyone in the apartment shifted uncomfortably.
"So you're not going to talk to me now? Not even going to acknowledge my existence, huh?"
Itachi didn't move. 
Harry  sighed. "That might be a problem." Harry grabbed the handle of his apartment door. "especially since my gift  is so awesome. In fact, it's  probably in a league of it's own."
Everyone, including Itachi, stared at Harry in surprise just as a loud crash and panicked screams filled the air.
Harry  smiled. "Perfect. I couldn't have timed it any better if I tried." He  opened the door and looked up at the large purple-scaled snake that was  leaning down towards his door.
Metal clinked behind him but Harry just looked up and waved, "Manda-san, over here."
The snake, Manda, made an odd gurgling sound, opened it's mouth wide and spit out an unconscious human body. 
"You owe me. Remember your promise, boy," Manda said, opting to speak like a human.
Harry nodded and hissed back. "A promise is a promise." He leaned down and pulled the unconscious body in to his apartment just as the snake disappeared in an explosion of smoke. 
"I really need to exercise more," Harry exclaimed as he finally pulled the body in to the apartment  and closed his door. Ignoring the confusion around him, Harry turned to  Itachi and stepped aside allowing everyone to get a better glimpse of  the body and said, "Happy Birthday!"
Itachi rushed forward. "Sasuke."
Naruto looked at Harry in confused awe. "How...What..."
Sakura stood still with wide eyes while Kakashi dropped his book. Everyone else seemed stuck in various stages of shock.
"After eavesdropping on some tiny snakes here, I learnt that   Manda had some problems, of the romantic sort. Some lady-snake he was  pining for wanted nothing to do with him,"  Harry said, "Anyway, long story short, I promised to help, act as a go-between. Since I spoke  'snake', he took my offer sincerely and the rest... well, it's pretty  obvious, isn't it?"
Yamato shook his head. "No, it isn't obvious at all. Stop skipping over the important details."
Harry waved off the questions and turned to Itachi. "Well?"
Itachi snorted but his lips twitched upwards. 
"I'll take that as a large squeal of joy and a proclamation of me  being the best friend ever." Harry turned around. "You know what'll make  this moment perfect?"
"A commemorative photo?" Sai said.
"No twitchy ANBU waiting on your roof?" Izumo supplied.
"Background music?" Kotetsu said as he slurped some syrup. 
Harry went in to his kitchen. "Cake! lots of cake."
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I  have to say, it's rather irritating/amusing/sad (mostly sad) that  people seem eager to pair Harry and Itachi together romantically (even  in AtO). What ever happened to normal friendship? It's like people see  no value in friendship.
Anyway, hope you guys are doing well,
Polar.
P.S. Why, yes, I do believe in the rare and absolutely-no-proof-from-canon ItachiXHana pairing. How nice of you to notice.