My son is not a very big talker and called Elmo "La-la"  as in "la-la-la-la  Elmo's World" while holding an elmo as big as him. Then, as his 2nd birthday drew near, he would say "elmo", "bbird", "rover","nernie",etc. so I knew we needed to have a sesame street party.  It was a little difficult to find party supplies that did not say 1st birthday so we had to improvise. We made our own invitations by drawing Elmo looking at Dorothy that said "I wonder what Dorthy is thinking about today" Then, when you pulled the tab, a think bubble (like comic strips use) appeared that said "birthdays!" and another tab showed a cake in Dorothy's fish bowl.  On the inside it said "Dorothy wants to know how do you celebrate a birthday.  Please come to Adam's party to show her on ..." and we listed date, time and our house. Since the guests ages ranged from 2 to 8 (and adults), I wanted to have activities so the older kids wouldn't get bored, but the young ones would enjoy it,too.  We have many sesame street toys and friends lent theirs,too, so everywhere you looked were the characters.  Also, on the walls, I hung up pictues that I drew on Oak tag of them, including the count with a big number 2 and Praire Dawn with the letter A (the number and letter of the day).  As guests arrived, they played with the toys and I purchased a big cardboard "color your own" play-house for the kids to decorate.  I had originally bought it to create Elmo's world, but we then decided it was the monster club house.  (You can order them on line, but I found it at Target.)It was fun to see the kids dance around to the wubba-wubba monster song and my older son took a stuffed elephant and chased the little monsters; both of which occur on the show).  We then gathered around the Count and we talked about the number of the day. Each child had to name something they had two of (eyes, ears, etc) inorder to get 2 bat rings. Since the older kids went last, they had to get creative.  The rings were from oriental trading co.  Then we moved on the Praire Dawn and the letter A.  As people started metioning things that start with the letter "a", my husband, on cue, took out our stuffed cookie monster who eats a pretend cookie making crumbly eating noise.  As he brought him near Prarie dawn's picture, the kids told Cookie monster not to eat it.  Then I suggested giving him a different cookie and showed them the pin-the-cookie in cookie monsters mouth I drew. (The mouth was drawn very big so the 2 year olds could do it.  The cookies were brown construction paper with blak dots for chocolate chips)  The kids played with the stuffed cookie monster while they waited so They were patient. After giving cookie monster a cookie, each child got a big cookie (costco) for sharing with him.  The older kids over-thought placing the cookie so much that they didn't do as well as the little ones.  Then drew attention to all of the pictures on the wall and someone noticed that Ernie was missing (I had intentionally did that) so we picked up our stuffed Big Bird and had a Journey to Ernie--also a stuffed animal I had hid. Since I was the only one who knew where it was, I gave clues like the show (ie. its under something) After they found him, everyone got a squeaky rubber ducky (Oreintal).  Then we played Sesame Street Bingo as we munched on goldfish.  (This was a lot of work because I needed to draw the pictures on the bingo cards and I needed enough pictures so everyone's would be different. Admitedly, I got a liitle desparate and used obscure things, too--like Bert's paperclip collection , B.Bird's teddybear Radar, etc., but I did have a help board for those who needed it) I didn't think the little ones would sit; boy, was I wrong.  This was a hit!! The adults got into it.  I was planning to play till everyone got bingo (or lost interest) and the prize was bubbles. Kids askes if they could keep playing and get bingo again so I let them. The buubles were from a package of wedding bubbles so there was 24 in a box and it was easy to print out labels with sesame street pictures from the internet.  While kids waited for food to be served, they created Elmo's world by coloring in pictures (sesame street characters) that I had drawn on shrink film.  (This can be purshased from an arts-n-crafts store. After coloring, the pictures are cut out, hole-punched, baked, and put on a ribbon to create a shrinky dink necklace.) We served pizza slices(cut in 2, of course) and sesame street juice boxes (Apple). (I was afraid of using an elmo cake mold since I can't pipe so I made a sheet cake and drew Elmo on it--2 marshmellow slices with upside down hershey kisses for eyes and a vanilla wafer cookie for the nose).  After we sang "happy birthday" and ate cake.  When the older kids asked what game is next, I just laughed and sank into the chair.  (I guess I could have musical faces... using sesame strret faces out of foam instead of musical chairs but hind sight is 20-20) As guests left they got a goody bag with their shrinky dink necklace, a small sesame street figurine, a pinwheel and the things they earned earlier --the bat rings, rubber ducky and bubbles. I'd say it was a success.