How do you get Rainbow Stars in PVZ GW2?

@PlasmaPea33 You get rainbow stars by playing the town hall events. The town hall is that one large building smack middle in the backyard battleground. It'll be to the left of the plant base and to the right of the zombies. Weekly modes are only available at the beginning of every month for a week or two and then you'll have to wait to participate in another.