A variation on the "container" is the hobby. Manga particularly offers many series that focus on characters exploring a favorite interest, including manga itself!
The hobbies range from camping to astronomy to stamp-collecting (okay, I haven't yet read a stamp-collecting manga, but I'm sure one is out there!).
Otomen is a great example--as is Hana-Kimi--of a series where hobbies define not only the series' theme but the characters. Frankly, more high school manga should employ the same approach!
Asuka, the main otoman of the series, likes cute things. Ryo, his girlfriend, likes physical, rough-and-tumble pursuits. More importantly, however, they like specific hobbies. Asuka likes cooking and sewing. Ryo is good at martial arts and likes to hike.
Amongst Asuka and Ryo's friends, Kitora loves flowers; Tonomine loves make-up. Juta actually has a job as a shojo mangaka.
The true magnificence of the series is that the otomen are allowed to be themselves--but so is everyone else, including the flirtatious girly girl whose hobby is, in fact, flirting and cheering people on.
The character are memorable because of what they focus on and pursue.
