Making music boxes, jewellery boxes and clocks is extremely satisfying to do. By having a daily use you also tend to look after it and admire the hard work that has gone into its construction and the story behind it, I have done numerous boxes and clocks and always find them fun to do. You can use pretty much anything for inspiration from a film, TV show, pets, favourite place or even just a pattern that pleases you.
When making music boxes I usually buy the correct size and style online then decorate it myself. This might seem like cheating but unless you need a very unusual type you cannot fault the cheap and readily available boxes online, although not the highest quality of materials they certainly do the job. Decoration can be carved on (make the box yourself as you will need thicker material), painted or using a pyrography tool (wood burner). The musical mechanisms can be purchased online with simple ones costing around £15 with many different tunes from classical music to TV themes. The mechanisms are often turned using a 'key' but hand cranked versions make the finished box more interactive, especially good for children.
Clocks are everywhere from your microwave, oven and phone to the old mantle clock your granny gave you. They are extremely useful and thanks to the internet components are readily available for very little cost. I would suggest a Casio mechanism as I have found these more reliable and widely available in both a standard style and pendulum design.