I had a Kindermusik party for my daughter's first birthday. It was fantastic. I was a bit skeptical that any activity would really interest 1 year olds, but it did. The instructor came over to my house and did about 45 minutes worth of music and activities, it totally captivated the little ones. My daughter smiled and laughed the whole time. It was so much fun! She brought shakers, music sticks, tons and tons of colorful scarves, etc. She even taught the moms and babies a dance to do together. I had never actually been to a Kindermusik class, but I had a friend who is an instructor back in Ohio and she was the one who suggested it. The other kids attending the party were right around 1- 1and 1/2, there was a 2 year old in the group though too... and he had fun as well. For snacks for the kiddos I had the traditional 1 year old snacky foods... puffs, cheerios, tiny cut up fruit, and I bought those take and toss sippie cups so that each kid could have a drink. I highly recomend cupcakes for the kids instead of pieces of cake. At age 1 it is so much easier for them to handle. And ask the moms to bring their portable high chair seats. It is nice when the other babies can sit and enjoy their cake with the birthday girl. But seriously, I highly, highly recomend the Kindermusik thing. She does all the work, and the kids have so much fun! The pictures I have from that day were great. Ali and all her little buddies laughing and enjoying the day.
I had her party in the late afternoon. You may want to think about the dinnertime thing, b/c a lot of kids that age go to sleep early... or get cranky in the evening.