I get the students working on their project and I use Youtube to create a dance playlist that I compile myself. Depending on the activity and location you can ask students to bring a snack that can be shared.
Examples of where I have done this...
Middle Years IT: A html coding party where dance music plays while students work individually on coding a website based on a scenario that I put together.
Middle Years History: I have played Gregorian chant in the background as students work collaboratively to design a 'medieval cookbook' and/or designed a medieval banquet.
IB Diploma: When the class have been working on a display on the Communist Revolution in China we have played Chinese Communist music from the cultural revolution and had snacks.