For my son's 4th birthday party, we opted for "The Sword and the Stone" theme. First, we made invitations on our computer announcing to all knights & damsels to attend festivities for Joey's birthday. For decorations, my son and I made colorful banners of coats of arms out of butcher paper & markers. We bought streamers in red, yellow, and purple and filled gold, silver, green, purple, and red balloons with helium. My husband and I made a three room castle, complete with drawbridge, out of big appliance boxes and spray paint (The kids loved playing in this). Matching tablecloths, papercups, napkins, plates and plasticware in silver, green, and purple were purchased.  On the paper cups, I hot glued "jewels" bought at local craft store.  When each guest arrived, he received his "sword" (plastic) and made his crown (cut out silver poster board which each guest decorated with "jewels," glitter, markers.  My husband and I rented medieval costumes.  Guests watched The Sword and the Stone, played "Slay the Dragon" (a dragon piñata), Hunt for the King's Ransom (I made a treasure chest out of an old box, hid it in the yard with a stuffed dragon and filled with goodies), and Merlin Says.  The big moment came when all of the kids were asked to join King Arthur's Round Table and were knighted by my husband, who has a replica of Excalibur. For goodie bags for the piñata treats, I glued fake jewels on ziplock bags. Turned out really neat.  For eats, we made Merlin's Magic Punch and a three story castle cake copied from a wedding cake.  Take home goodie bags contained a story book of knights, magic rocks, stickers of knights, queens, and kings, and party horns. This party was alot of fun. Now, I have to outdo it this year.