NOTE: this game is in alpha. Only three levels out of a planned eighteen or more are currently available.
Need some low-fi hip-hop radio, with beats to relax/study to? Why settle for storebought when you can make your own? Hidden in each of the charming pictures are multiple musical instruments. Each one you find will open up a rhythm game; match the notes and they'll continue to play. As you find more instruments and add them to the piece, everything will slowly come together.
And the hidden object/rhythm gameplay isn't all there is. Click on that confusingly-named Random Beat button to find the Edit Beat feature, and put together your OWN SONGS, entering the notes on the rhythm-game screen and then recording samples to assemble. When you've finished, you can export your beat as a (long) password to share with others, who can use the Import Beat function to play your song on their copy.
Not only does this work great as a game, but it's also a musical toy that lets you compose your own multi-instrument pieces without even needing to read sheet music.
This is also a great game for kids. It's easy to use and the beat-editing feature could get a budding composer started -- I could give the usual spiel, but I think by now everybody knows that learning to play and understand music not only provides a valuable skill but also improves cognitive function, mathematical ability, self-discipline, etc.
Windows/Mac/Linux or play in browser.