For my son's 2nd birthday, we had a Clifford party. The invitations had red dog paws and said "The Big Idea for today is a party you can't miss" then the details of the party.  When the kids arrived, we transformed them into little Cliffords. I pre-cut red dog ears and had the children color or put Clifford stickers on them. We stapled them to construction paper strips and fit them around their heads. My neigbor painted dog faces on all of the children.  I had a picture of Clifford's dog house enlarged and laminated. I cut a slit up the middle and hung it in a doorway. The kids loved running through it.  I also made all of their pictures in front of the dog house and included it with their thankyou note.  We served a Clifford cake purchased at a grocery store and served it in dog bowls along with ice cream. Other food on the table was displayed in larger dog bowls. We played pass the "hot bone" (like hot potato) to the tune of who let the dogs out.  This game was a little advanced for a group of two year olds. Once they had the bone they did not want to give it up!  We didn't schedule every minute and just let the kids play outside.  The goodie bags were brown lunch bags with "___ doggie's bag" written on the outside.  Inside were little dog bone cookies that I made, Clifford stickers, a tennis ball with dog paws and other little toys purchased at the dollar store.  I'm working on my son's 3rd birthday party now and love getting ideas from your site.