When I have a list of songs that I want to review, I bring the surprise sack. I put a number of my song review aids in here and have the children draw one out to use with each of the songs we sing that day. I regularly use the bell, the baton with a fancy on it, the glove, the color cube, the slinky, rhythm sticks, puppets, and always a wiggle worm or a wooden heart for choosing a favorite song. I've explained these aids elsewhere in the blog. You can look under the music aids label or the reviewing songs label.
I also use the surprise sack on the weeks I'm teaching a song. I can put few fun things in the bag for when the children get restless or need a change of pace. We can stop and pull something out of the surprise sack.
I made my sack many years ago out of rugged corduroy fabric and it has held up well. You could easily substitute a sturdy gift bag instead.