I'm assuming everyone know what a "sinful pleasure" is: it's something we secretly enjoy (a food, a movie, a piece of music) which we'd NEVER admit to enjoying in a group of people for fear of having that thing thought of as being "tacky" or "maudlin".
If you're a guy, a "sinful pleasure" might be a movie like Steel Magnolias or Terms of Endearment.
If you're really into food, it might be a secret passion for "Royal Instant Chocolate Pudding". (Yes, I can make my own sushi and the classic Pot au Feu with the standard accompaniments -- but I love Royal Instant Chocolate Pudding.")
In this case, it's music. Do you have a "sinful pleasure" in music that you'd never own up to telling anyone?
Here's mine: George Enescu's Roumanian Rhapsodies No. 1 and 2. No. 1 is a potboiler, with tune after tune after tune after tune -- but it's really, REALLY fun to listen to!
The other one: Johann Strauss' Blue Danube Waltz.
What's yours?