My son just turned 4.  We had a Fire Truck themed birthday party.  We called up the Fire Department and asked if they could come out to the party (either for a small donation or to give a safety demonstration). They were delighted to do so.  I informed all of the parents ahead of time that we were having the fire trucks come at a specific time so as to make sure that the kids were there on time. Then I sent each of the kids the invitation.  I bought all of my supplies at nearby party stores, including piñata, table covers, and fire truck balloons. I scanned a picture of a fire truck and took it to the bakery and had them make a cake with the same fire truck as all of the invitations.  Decorating:  Each child's place at the table had a fire truck balloon attached to it and the birthday boy had four (for his age). We had healthy snacks (crackers, cheese, apple and orange wedges with juice) laid out on the kitchen table at a level where the kids could come in and take a snack.  When the kids started to arrive (about 1/2 an hour before the fire trucks), we just let them play on the front lawn with a soccer ball. This way, when it was time for the fire truck to come, they could all watch it come roaring up the street.  I think the parents were just as excited as the kids.  All the kids got a fire hat at the beginning from the fireman.  Then, they each got a turn to spray the water hose on the truck. Then they each got a fireman's badge.  After that, they each got a turn up inside the firetruck and got a chance to talk on the CB radio. The fireman were gracious to take pictures with all of the kids and then the birthday boy.  When it was time for them to leave, all of the kids took their turn hugging the fire chief.  As they drove away, they turned on the siren and the lights were flashing. Of course, aside from the kids, all the neighbors were outside enjoying the show, too.  After they left, it was an easy transition to the piñata and then inside for cake, presents and favor boxes.  The favor boxes were all pre-assembled and sitting on a high shelf. They were, of course, in the shape of fire trucks.  Each child had his or her name printed on the box and the only thing inside were lots of toys.  It was great. The parents had a great time and so did the kids. For thank yous: We took the firemen a plate of cookies the next weekend.  They were simply grateful.  In their combined 30 years of service, that was their first birthday party.  For thank yous to the kids, we gave the parents a thank you note and pictures of their child spraying the hose, sitting in the truck and hugging the chief good-bye.  All involved were grateful, and my son still talks about it. His fireman's hat sits on the shelf in his closet.