I'll admit, I used to be a big "buy lots of little things and put it in a bag" party favor kind of girl. As Madelyn has gotten older, I have definitely gone away from that thinking. Don't get me wrong. I don't think there is anything wrong with it. I am just not a "stuff" girl. I try to give one or two things to the kids and often will make it be a craft or something they have made. The boys are too young (and totally not interested) to do any sort of craft/favor project, but it was still a pretty easy decision.
I ordered the Construction Hats off of Amazon, but I know you can get them at various places. I printed labels with the kids names and placed them on the front of each hat. I always personalize when I can. The hats then were used as part of the decorations up on the deck. Again, making them work double duty! I also had the boys were their hats when we sang Happy Birthday and we took a group shot with all the kids and their hats. I also went to Home Depot and picked up a bunch of Nail Aprons for $.77 each. Seriously the kids were thrilled and I didn't spend a lot. Win, Win! The kids each took home a set of Old Dirt Road Pops as well.
As for activities, well I knew the pool would be enough. I did want to atleast have one game, so again I went to the playroom and collected a bunch of the boys tools. I took a photo of each tool I collected and made four different scavenger hunt sheets.
Then I broke the kids up into four groups, making sure to place an older cousin with each group. The kids had to go around the back yard and find the hidden tools that was on their scavenger hunt sheet only. We hid the tools earlier in the day while the boys were "napping". This game was a HUGE hit! It took longer than expected, which was totally fine. I hate when you plan out a game and it ends up only taking 2 minutes! When everything was found, the boys wanted to play again, so I had their older cousins rehide them. I even kept the sheets and laminated them so we can play in the house.