My daughter just loves the Wizard of Oz, so we chose the movie as the theme for her fourth birthday. I was so inspired by many ideas on this site, and the party was a huge success.  Invitations featured a whimsical illustration of the characters, printed on vellum and tied to a card with gingham ribbon.  Through a window in the vellum, guests were invited to Follow The Yellow Brick Road.  On the card, we asked everyone to meet at Munchkinland (aka the local park). My daughter wore her "Dorothy outfit," which is a lavendar gingham dress, lavendar socks, ruby slippers, with her hair in braids with matching ribbons.  She was so cute and soo excited.  This theme really lends itself to amazing decorations. We used blue and white check fabric to cover the tables, and weighted them down with bricks painted yellow.  Centerpieces were cubes of styrofoam painted green, with "Tootsie Poppies" (tootsie pops stuck through red cut-paper flowers), surrounded by four of the yellow bricks. This was so cute!  We also had a scarecrow sitting on a bale of hay, a painted apple tree, a tin man (made by my husband from objects found at his commercial construction job) and a lion.  A papier-mache hot air balloon hung from a tree and carried a birthday message for my daughter, and the basket acted as a handy spot for wipes, sunscreen, and first aid items just in case.  There were plenty of balloons in rainbow colors, including ones that read, "Wizard of Oz."  Also, a monkey pinata, with wings attached, flying in the air. I also used some wizard of oz streamers I found on eBay (Wizard of Oz party items have been discontinued -- I found plates, napkins, etc. on eBay). When the kids arrived, they chose from a rainbow of gift bags, and decorated with glitter, Wizard of Oz and rainbow stickers, and crayons. When all the guests had arrived, Glinda the Good Witch (a good friend of the family dressed in costume) showed up to wish my daughter a happy birthday and pass out special "Glinda Bubbles" to all the kids. These were small bottles of bubbles with labels printed from the computer.  Then, the kids had a variety of games to choose from -- each with its own prize.  The Scarecrow game had a bag of items, and three suitcases each labeled with a picture of a movie character -- the scarecrow, Toto, and Glinda. Kids reached into the bag and tried to figure out in which case the item belonged -- the scarecrow had an old hat, an ear of dried corn, and some raffia (extra straw).  Toto's case had a dog toy, a bone, and a leash. Glinda's case included a tutu, crown and wand from my daughter's dress up collection.  When kids successfully placed all the items, they received a "diploma" -- Oz coloring pages copied from the Internet, rolled and tied with raffia. The next game was the apple toss -- my husband made an apple tree using a cardboard cylinder as a trunk, and attached a backboard that looked like the top of the tree.  Kids tossed apple beanbags, and won an apple for their treat bags. They loved this. The tinman game was definitely the most popular -- the heart on the tinman game. My daughter and I made heart magnets using salt dough, painted them red, and I hot glued a magnet back to each and painted each with a guest's name.  The kids found their heart, and tried to place it on the tinman while blindfolded.  It was fun and so cute, because when they placed it just right, each kid's name was in the heart of the tinman. The hearts were also favors. Another big hit. To earn their "Badge of Courage" (printed from the Internet, strung with yarn and decorated with glitter), the kids ran through the "Tornado Tent."  This was a shade tent we set up, with strips of ripped sheets I'd dyed gray hanging from the top. It was a breezy day and the strips were blowing in the wind -- the kids just loved running through and it was also a cool place to hang out.    We served platters of fruit and veggies in rainbow colors, and ranch dip for the veggies.  Also rainbow Goldfish crackers, different color tarro chips and regular potato chips. For the kids, I made "Wandwiches" -- PBJ cut into a star shape, with a pretzel stick serving as the wand handle.  The kids ate them like popsicles and loved them!  For the adults, we ordered sub sandwiches and sliced them up.  We put a sign above the drinks cooler that read "Melted Witch Watering Hole" and a witches hat hung from the sign. The cooler was filled with green drinks -- kool aid coolers, sprite, perrier, green apple juice sodas, etc.    After the lunch and the pinata, it was time for cake. With the help of a sandcastle bundt pan, I made a yellow brick road leading up to an Emerald City.  To make it look more authentic, I used sugar cones iced and rolled in green sugar atop the sandcastle's turrets.    This party was a terrific family project -- in the weeks leading up to the party, my daughter helped make the heart magnets, the courage badges, the centerpieces, the papier mache balloon, and helped her dad make the tinman, paint the bricks and build the tree for the apple toss.  We all baked the cake together, and my daughter drew several colorful OZ pictures to hang up around the party site. All in all, it was very cost effective because we made so many of the party's elements ourselves. All the guests, young and old, seemed to appreciate the party's classic feel.    Hope these ideas will inspire you, as I was inspired by other ideas on this site.