Here's a great picture from 1963, and none other than Mickey Mouse himself poses with two fans. I like some of the details, such as big sis's rainbow-striped dress and her ticket book, or the popcorn box in that other's girls hand
Check out this neat certificate that would have been issued to kids. It is signed by "Ginny" - Ginny Tyler, who went on to become a "Disney Legend" in 2006. From that official Disney Legends writeup: "When the original "Mickey Mouse Club" was re-edited and repackaged for syndication in 1962, Tyler was appointed Head Mouseketeer, live from Disneyland." She also provided the narration to some of the beloved Storyteller albums, including my well-worn "Peter Pan" record. I can still hear her saying, "I'm a codfish"! You had to be there.
Another neat souvenir is this metal button.
Here's an Official Membership Card. It's neat, but not as neat as Matterhorn1959's mint unused example!