What are some ideas for a birthday celebration for a 4 year-old boy?

Birthday celebrations for 4 year-old boys are a great occasion to bring people together and make the birthday boy feel loved.  Here are some great ideas that may be perfect for the 4 year old in your life:
1. Pool Party - If you have access to a pool, having your party with the pool being the centerpiece is great fun.  The kids can swim and splash while the parents visit together on the deck.  Food, drink and birthday cake are essential to the fun!  Just be thoughtful about keeping the eating and swimming as two distinct activities during the party.
2. Pizza making party - This is great for the kids and the parents alike.  You can get fresh pizza dough from most any grocery store.  Have bowls of sauce, mozzarella cheese, meats, and vegetables that each member of the party can choose the ingredients they want on their pizza. Let each person make their own.  Have the oven hot and ready to cook the pizzas as your guests prepare their own special concoction.  While people are waiting, you can do things like have games, have a sing-a-long, or just visit.
3. Outdoor organized games - Pick four or five organized games and have some of the adults be the facilitators.  Divide the attendees into teams, mix the teams up and just make sure everyone is being included.  After the games, or at a halfway mark, break for food and cake!

These are just a few ideas.  Let your imagination run freely.  Anything that creates fun, includes everyone, makes the birthday boy feel loved and includes food, you'll have a winning celebration!