Making sure the house is decorated with nothing but Mickey Mouse decorations is a must when it comes to throwing a Mickey Mouse Clubhouse birthday party. Banners and streamers are great decorations, but there also should be plates, cups and napkins adorned with the happy mouse. A cake in the shape of Mickey's head works great for this party theme.
Party games that have something to do with Mickey are a great idea. Games such as "Pin The Ears On Mickey" keep the kids happy while staying inside the theme of the birthday party.
Another way to make sure the guests feel as though they are actually inside the Mickey Mouse Clubhouse is to play movies that star the iconic mouse. There are plenty of Disney movies out there that have the character as the centerpiece. Plan a movie marathon with some of his best work and the guests are sure to enjoy watching all of the fun unfold. Hand out small toys and figures of Mickey as party favors. This really pulls the theme together.