One of my most favourite class at gym is Body Balance. The first few times of class had me really pushing myself very hard to stay balanced. I had the "shivering" legs and knees, which of course the instructor said was part of learning. Once i got over that stage, I now can stand without actually wobbling all over.
But having a great workout itself is only one part of it. The reason that i find the class a must-not-miss is the music! The song selections are marvelous and most of all, inspiring. Let me share with you my top 2 tracks:
It's Amazing by Jem
Look No Further by Dido