|From Harry Potter Wikia|
Apparently, Ms. Ravenclaw came up with both the name of Hogwarts, it's location, and designed the floor plan.
At some point, she had a daughter, Helena, who stole her mother's diadem (think: smallish, pretty crown), which broke Rowena's heart. When Helena died, she became the Gray Lady, Ravenclaw's ghost.
Like Hermione, she was described as the greatest witch of her time.
Ravenclaw House "a sharp mind, wisdom, creativity, and cleverness in its members."; the colors are blue and bronze; and the symbol is the eagle. It's common room/dorms are located in a tower. Noted Ravenclaws are: Luna Lovegood, Professor Trelawney, Cho Chang, Moaning Myrtle, Padma Patil, Professor Flitwick, Mr. Olivander and Gilderoy Lockhart.