We started our ninja training with the headbands, you can't be a ninja without looking the part, right? I made this with a simple white woven and fabric paint.
Our party games started with an obstacle course. As a ninja you have to move quietly and quickly without touching the ribbons, obviously. I added a game component were they had to fetch a balloon on the other side and return with the balloon. The kids loved this and couldn't get enough of it... until the present 3 year old just ran through and the game was over.
Perfect timing for the next game, ninja star throwing in a couple of bowls. This involved some origami preparation from my side, folding the ninja stars. You can find a lot of tutorials on this all over the web.
After these three games the kids were definitely in need of some outdoor activities and we did a little treasure hunt, following the ninja stars I hid outside.
Our last game had a quiet approach: sensei is sleeping. One kid sits on the ground and some of the others get up behind him and the sensei has to guess how many kids are there. A true ninja can sneek up really quietly off course!
We ended the party by making Japanese straw hats they could take home. An easy craft the kids really enjoyed. Just cut some large circles ( I used wallpaper), let the kids go wild decorating them, cut into the middle of the circle, let the pieces overlap and tape them together.
Once the ninja invasion was over we could happily crash on the coach, mission accomplished and the kids had a blast!