Hi from Shreveport, Bret! For nine years, WAY before I found this wonderful site, I have been using a reward day where the children bring their own music. Mine are elementary, but they bring rock, country, etc. I have a rule that there can be no vulgar language--zero tolerance. I tell them if I ever hear a bad word, no more bring your own music days. But in nine years, no one has violated it. In fact, they will bring me a CD and say, Don't play track#X because it has a bad word.
If you don't trust your students to do the screening, you might spend the dollar to download something popular off the top ten on iTunes or something. To prescreen, you can usually find the lyrics on a lyrics site. I have a good one somewhere. (There are plenty of those sites that aren't good.)
My students are always asking if they can bring their iPods. That is against school rules. But I am thinking of asking my principal if I could have an iPod day. They could bring them to me first thing in the morning (in labeled baggies) and I could lock them in the closet till time for music, then they could get them at the end of the day or something. I use my iPod in a BOSE speaker at school and that is motivating to them.
I also reward them by showing them a cool app on my iPhone. I have one called Tempo that is a virtual metronome and has a tuner on it. too. They love Ocarina (flute...blow in the mic to play it) and guitar and for the little ones, there are sound machines. They like Vehicles and I let them touch the vehicle of their choice to hear the noise it makes. Or we play "guess the vehicle" for sound discrimination. I know that is elementary, but maybe you could think of a way to adapt the ideas.
I love someone's idea of a karaoke day...plan to use that. We could preplan...kids could tell me what song they want out of what we have learned in class and I could send them to Garageband and take the vocals off as necessary.