I've been doing an in-home program with one of the autistic kids I work with during the school year. This particular child is 4 and has a difficult time with bathing, so I suggested some water play for some of our time together.
Of course the first thing that comes to mind for me when someone says "water" is kayaking, so that's what I suggested (along with wading in the lake).
Special needs kids often "stim" (self-stimulate). Some do hand movements, others twitch or pick at something or sift sand/dirt/rocks, this child vocalizes, but as soon as we were in the boat she relaxed, quieted down and was calm.
I paddled my little friend all over the lake, looking at the ducks and geese, going through the tullies, checking out trees and fish, and stopping to put our hands in the water or sprinkle water onto her feet for an hour and a half. An HOUR and a HALF! I thought she might last 15-20 minutes, but she was so content we just kept on going. It was awesome.
The getting paid was second to having a successful and fun outing with this little one.