How about putting them in a big circle, distribute some chocolate coins (or hard candy?) and teach them to play a game of dreidels... After playing it a couple times with everyone in a circle, divide them into smaller groups:
http://en.wikipedia.org/wiki/Dreidel
You don't have to emphasize the Hanukkah/religious aspect... at age 5-6, the kids will enjoy justing playing the game for the candy/treats.
Each player starts out with 10 or 15 "coins" (pennies or chocolate, nuts, raisins, candies or other markers), and places one marker in the pot. The first player spins the dreidel, and depending on which side the dreidel falls on, either wins a marker from the pot or gives up part of his stash. Start the game with at least something in the pot, so if the first person spins a 'take' then there will be something there... If you play it in a big circle group, just keep refilling the pot if someone wins it all before all the kids get their turn; just pass the same driedel to the next player. (If played in a big group, the pot has the potential to get big! which undoubtedly the kids will love). The game's code (based on a Yiddish version of the game) is as follows:
Nun - nim - "take" - the player takes one from the pot
Gimel - gib - "give" - the player puts one in the pot
Hey - halb - "half" - the player takes half of the pot, rounding up if there is an odd number
Shin - shtil - "still" (as in "stillness") - nothing happens and the next player spins
The game may last until one person has won everything.
And, if you need something more to fill up time, you could also teach the kids the dreidel song. The words are non-religious:
I have a little dreidel. I made it out of clay.
When it's dry and ready, then dreidel I shall play.
Oh dreidel, dreidel, dreidel, I made it out of clay.
Oh dreidel, dreidel, dreidel, then dreidel I shall play.
It has a lovely body, a leg so short and thin.
When it gets all tired, it drops and then I win!
Dreidel, dreidel, dreidel, with leg so short and thin.
Oh dreidel, dreidel, dreidel, it drops and then I win!
My dreidel's always playful. It loves to dance and spin.
A happy game of dreidel, come play now let's begin.
Oh dreidel, dreidel, dreidel, it loves to dance and spin.
Oh dreidel, dreidel, dreidel. Come play now let's begin.