I would need to visualize machine state in time. Basically the machine is in one of the finite number of states (e.g. producing, waiting for material, broken, out of paper, whatever).
The graph should look like this 
- some horizontal bar where color represents particular state and x-axis is time. (Also hovering over the state should show popup with detail - state description, duration, etc.)
It seems quite trivial case but I have no idea what type of chart should I use. Any idea?