One of the best skills a young one can learn in Aikido class is FOCUS.
The program in which I taught had this following mantra:
Sensei: What is the first rule of Aikido?
Class: FOCUS!!! (the louder the better)
Sensei: What is the SECOND rule of Aikido?
Class : FOCUS!!![
To this I added,
Sensei: What is the THIRD
Rule of Aikido?
Sensei: No, no, the third rule of Aikido is 'don't forget the first two rules'
(And yes, the wink is important)
A fellow teacher stumbled on "The Focus Game" which was really just a way to get the class settled down and focused again. The last version I used worked as such:
1) Everyone stands in a circle and "focuses" (standing straight, no excessive fidgiting, no talking, etc)
2) If a student loses focus, they sit in seiza and "get thier focus back" when they are suffeciently focused they are invited to stand back up.
3) When the entire class can go a minute (or however long Sensei says shorter or longer) with everyone staying focused, the game is over and EVERYBODY WINS!
Variations on the focus game can have Sensei or the assitants doing things (sudden claps, stomping on the mat, making silly noises, sudden breakfalls, etc.) to break thier focus and make them giggle. Soon they will be able to stay focused even with that kind of ruckus going on.
BEST OF LUCK!