Speaking of drabbles, here's one I wrote because Cravache said that she'd never received a Valentine before.
A Valentine For Cravache
Wistfully, Luna watched the owls stream into the Great Hall on Valentine's morning.
She didn't really expect anything, except for the usual gift of chocolate snorkacks from her father. After all, who would send Looney Lovegood a Valentine? (Except for her father, of course.)
Hecate, her father's owl delivered her load of chocolate, then left.
Then a snowy owl landed near her. A quick look confirmed that Hedwig was perched next to Harry.
This owl bowed and held out its leg.
Luna opened the package. It was a chocolate rose with a note.
"Happy Valentine's Day from your Secret Admirer."