.. But not music class
Another teacher at my school sent out a link to Focus at Will
You have to create an account (they have a free trial which as far as I can tell lasts for ever just with limitations) to be able to access the music but apparently it is supposed to help you (or your students) sharpen your focus on whatever task you are doing and keep you on task longer.
I haven't used it much in my classroom (only when my grade 8's are requesting music and then groan when I turn this on because it isn't the radio). So I can't say how well it works but the research seems to be legitimate. I'm going to make more of an effort to use it in my classes over the next couple of weeks and report back with more thoughts.
With the free trial you get 60 minutes of listening time. I think after those 60 minutes you just have to restart it and it will no longer be new music (so basically it will be a repeat) but classes generally aren't much longer than 60 minutes anyways AND they have about 10 options under the free trial so if you have the same students all morning (like I do with my grade 4's) you could just play a different theme.
Others should try it too and report back their thoughts. You could also use it at home (the teacher who used it at my school used it while she was writing report cards and says it seemed to help her) but it is suggested that you don't use it as background music while you are eating dinner or chatting with friends for example because that is not what it is intended for.
What are your thoughts on Focus at Will?