So, if you're a church-going sort, celebrate this feast day by thanking your church musicians. Many of them are working for small salaries (or for free), and they probably don't hear many words of thanks.
St. Cecilia is also the patron saint of music and musicians of all kinds. It seems appropriate to celebrate this feast day by listening to music.
Here's a picture by Botticini; are they playing instruments?
I love the idea of Saint Cecilia inspiring all sorts of music festivals throughout the ages; she continues to inspire musicians today. Her Wikipedia article's largest section covers the many ways that artists in the last half of the 20th century wrote music inspired by her.
I am less comfortable with the idea of her fierce dedication to her virginity. As a feminist scholar and theologian, I’ve grown a bit uncomfortable with virgin saints, like Cecilia. She's more interesting than many, as she was married, and convinced her husband to accept her virginity. She's one of the virgin saints not martyred because of her virginity.
The lives of these virgin saints show us how difficult life is in a patriarchal regime. It’s worth remembering that many women in many countries don’t have any more control over their bodies or their destinies than these long-ago virgin saints did.
Perhaps instead of celebrating this feast day with music, we might want to support a social justice organization that helps modern women in patriarchal countries where they have few rights.
But of course, we don't have to choose: we can support women in less-developed countries, and we can support our local musicians. Let's do both on this feast day of Saint Cecilia!