Are you talking family party or kids party?
For the kids party (which consisted of DS and 2 of my friends' babies) we got some of those plastic ball-pit balls, and put a 2-deep layer of them in the playpen. - They really don't expect much at 1.
We also had the the same style carousel cake that I had at my first birthday, which was kind of neat sentimentally for me. (The babies just liked playing in the frosting.)
For the family party, we made up a list of questions - favorite food, favorite "sport", what will he be when he grows up?, etc. We had all the guests fill it it out with their guesses for the answers at 1yr, 4yrs, 10 yrs, and 18 yrs. We declared a winner for the most matches at 1, then sealed the others in envelopes to be opened at those parties. - It was so much fun when he turned 4 and people read and remembered their answers and compared them to his current ones!