Yamada-kun to 7-nin no Majo (Yamada and the Seven Witches): When bad boy Ryu Yamada falls down a flight of stairs with class brainiac Urara Shiraishi, he is knocked unconscious, and awakens to find that he and Shiraishi have swapped bodies. After a failed attempt to swap back by falling down the stairs, Shiraishi realizes that they accidentally kissed on the way down, and she and Yamada learn that they have the power to swap bodies by kissing. The bulk of the TG content is at the beginning of this manga, and while it becomes less frequent as the other witch powers surface, it still pops up throughout the manga.
Boku wa Mari no Naka: Isao is a college dropout loser, who sits in his dirty apartment, eats crap, and plays video games. The highlight of his day is going to a convenience store, where every night, he gets to see a beautiful high school girl. One night, he follows too closely as she walks home, and passes out when she turns back to look at him. When he wakes up, he finds that he's become Mari, his "Convenience Store Angel"!
Fukigen Cinderella: Haruhiko Kanna is just an ordinary man with an ordinary life. One day he meets 3 witches in a small room in the old clock tower, and that's when his ordinary life became not so ordinary at all. With the curse, or gift, he was granted that he'll change to a girl once the clock strikes 12 Noon, and will return to his male self at 12 Midnight. He then asks himself, "What on earth will happen if this goes on? Can I survive like this? Most of all will I turn back to normal again?!"
Your and My Secret: From Wikipedia - The story revolves around high school student Akira Uehara, sensitive and demure by nature. Despite that he has a large crush on the most feared and violent girl in school—Nanako Momoi, who seems fragile and cute, until she opens her mouth. One day Momoi is absent from school for unknown reason and someone is needed to bring her homework to her. Though most students push it off to each other, Uehara willingly volunteers to bring Momoi her homework. He arrives at her house to find it unlocked and seemingly empty. He enters and stumbles on a secret passage, which leads to the laboratory of Momoi's mad scientist grandfather, who is using his own granddaughter as a test subject of his new invention.
He is about to save her, but the situation turns on him for the worse when Momoi successfully persuades her grandfather to use Uehara. In the attempt to get Uehara, Momoi's grandfather accidentally presses the lever that activates the machine and the end result is that Momoi and Uehara have switched bodies. The story is told from Akira Uehara's point of view and details his frustrations with trying to get things changed back and with some things that girls go through, and the small unexpected pleasures he gets some days, because he is now outwardly a girl. He worries that the longer he stays outwardly a girl the more he will become, inwardly, a girl.
I may have a few more lost in the shuffle of my bookmarks, but that's it for now. Also, I'd like to point out that Yureka was published in the U.S. under the name "iD_eNTITY".