Whats this I hear about One Flower Wednesdays?

My step sister told me about one flower wednesdays! I want in! How do I go about this? Who do I talk to? Whats involved!?! I wanna be invited. My step sister would never steer me wrong! She's  the reason I have my cat after all. And in case I forgot to thank you for him I'll do it now! Thank you!!!