I bought the flag at a Field & Stream store. It's a Yakattack flag: http://www.yakattack.us/FJR_p/fjr.htm
The pole and orange flag are the Hobie Visicarbon Pro.
The decals I got from http://military-graphics.com/
We're going camping next week and it should be warm enough to have a water gun fight on the lake. We had a couple last year. The mirage drive should give us both an advantage at being able to hose each other down. This video was taken last year after we got our first kayaks: https://www.youtube.com/watch?v=Rnshh-OfkTM
You've got to get the water guns and have the "naval battles" to get the kids interested. Be prepared to get soaked a lot. I don't expect anyone to watch the entire video as it was meant for friends and family but you can see how much fun a kid can have in a kayak with a water gun.
For his birthday, last year, I got his friends and classmates together for a canoe party. The canoe livery nearby had a great group rate and everyone had fun even though the river was down and some boats ran aground. Getting a group together with the child's friends makes the experience of being on the water that more enjoyable.
I don't expect anyone to watch the entire video but go to the 5 minute mark and watch how this kid keeps a cool head when things didn't go so well: https://www.youtube.com/watch?v=07BQF3sTDA0