T.L.
Before our daughter, we use to do some serious partying for New Years - fly to a great location with another couple, go to parties, have parties, stay in hotels and go to their parties, etc.. When our daughter came along, all that changed.
Our daughter is now 13 (almost 14) and in order for her to have a good time and know where she is,plus we too have fun, we throw a party inviting parents and kids. We have games, poppers, sparklers (things you buy at Target and can have in the city), sparkling juice for the kids "Champagne", and all sorts of finger foods. The kids have a blast.
The adults play cards or the latest adult board games and have some alcoholic beverages along w/soft drinks, cider, tea, etc... Since most everyone has kids the alcoholic drinks are kept to a minimum plus you can always leave it out.
For the babies and very small kids, we have a separate place for them to be on pallets in the floor with age appropriate toys. They seem to have fun figuring out each other. All the parents take turns entertaining the kids and making sure diapers are changed, older kids aren't hurting each other, potty breaks are taken, etc.. It is so much fun and there is no babysitting fee. For the older kids we make a big deal o ut of watching the clock and they have a blast at midnight.
Good luck,
T.