Super Mario Galaxy 2/Beat Block Galaxy

Star 1: Step to the Beep
Like the Star's name said, step to the beep. Then, once you get to the pyramid, collect the five Silver Stars and the Power Star will appear at the top.

Star 2: Silver Stars in Double Time
This is exactly the same the Step to the Beep, except that everything is four times faster than usual. Follow the instructions on Step to the Beep, but remember it's going faster than usual.