A Glaring Blind Spot

For Christmas, my parents both wanted MP3 players filled with music.  For my mom, that's not tough.  She's like me and, even if she isn't familiar with something, will listen to it anyway.  My stepfather, though, has pointed out that in my expansive, eclectic knowledge of music, I have a glaring blind spot with which I was okay until now.  He wants...disco. Help.