Parvati and Padma Patil
"Come on! We're supposed to dance!"
-- Parvati Patil to Harry
Parvati has long dark hair which she wears in a plait. Harry by his fourth year thought her very pretty, while Dean Thomas considered her and her twin to be the best-looking girls in their year (GF23). Despite this, apparently neither girl had an escort to the Yule Ball of December 1994 until very late, when Parvati agreed to attend with Harry, who asked her after being turned down by Cho Chang (GF22). Harry was a rather disappointing escort, paying Parvati very little attention, and Parvati took up with a boy from Beauxbatons instead (GF23), and was somewhat cool toward Harry for quite some time afterward -- understandable on the whole, since he had ignored her vexation. Parvati wore robes of shocking pink with gold bracelets and braided her hair in plaits with gold.
Parvati fought in the Battle of Hogwarts (DH29).
Boggart: a mummy (not a cobra, that is only in the movies).
parvati = the name of a Hindu goddess, the consort of Shiva (hindunet.org).
patil = a Hindi term used in central and southern India to refer to the head of a village (NSOED).
Other names: Professor Binns, never a good one for names, calls Parvati 'Miss Pennyfeather' (CS9).
Padma attended the Yule Ball in her fourth year (December 1994) with Ron Weasley, as a blind date arranged through her sister and Harry Potter (GF23), but it did not go well (GF24). Padma wore robes of bright turquoise (in the movie she wears pink and orange).
Padma was made a prefect in September 1995 (OP10), and joined Dumbledore's Army in October of that year. It is not known whether her attendance at the first meeting of what became Dumbledore's Army (OP16) was arranged through her sister Parvati, through Hermione Granger as a fellow prefect, through Ginny Weasley's connections in Ravenclaw House, or some combination thereof.
Padma fought in the Battle of Hogwarts (DH29).
In the Movies
In the movies, both Patil sisters are in Gryffindor.
Padma is played by Afshan Azad (IMDb).
Interview of Shefali and Afshan (cBBC).