Kids Game Ideas???

~Get some bur-lap sacks and have potato sack races.
~Have them tie legs together and do 2-legged races.
~Have small balloons and have balloon tosses. The last pair standing wins.
~Have some puzzles where the kids work with the adults to figure out like
_______
READ
_______
means read between the lines. Both adults and kids love these and they can work together.
~Do find your relative Bingo and both kids and adults play. In the boxes have "Someone who ate fish for dinner last night. In another box, find someone that has swam naked.... " These are always fun because the kids feel they find out things about the adults and the adults and kids work together.
~Another both can do is form teams and have everyone have big serving spoons. They scoop up an egg, walk 25 feet and transfer the egg to the spoon of the next person. Then that person walks and transfer the egg without dropping to the next. Then the final person has to place it on a ledge, chair or something without dropping it.The first one to complete wins.
~Make sure you have a "Soul Train" dance line. All like to watch others dance.
~Have an ole school v/s modern dance off. Have the kids come in the circle and dance. They did point to an adult and have them come in the center and dance after them. Both do dances from their era. This is not a win loose thing, but soooo much fun.
~Have a few arts and crafts set up for the kids. They can make bird feeders or beaded jewelry (string and beads). Order from a place like Oriental Trading some of those cardboard frames, also found at many dollar stores and let the kids decorate them.
~Pack a couple of Frisbees, they are cheap and easy to pack.
~Ball pitches. Mark with tape a bulls eye and have people toss balls (You can get little plastic ones from the dollar store) to the bulls-eye. Who ever comes closer wins.
I hope this helps and will come back to edit the answer and add if I think of any others. BTW.... I would get all of the items before you leave and mail them in a box to one of the relatives who lives where the reunion is going to be. I would not carry it all with me. The stuff that I mention can all fit in a flate rate priority mailing box and therefore will not cost much. Good Luck and have fun.

scavenger hunts, water balloon wars. water guns, 3 legged race,
are all fun, egg on a spoon race.
Just think, elementary school field day.

I would enlist the help of any teen that wants to help. Perhaps send out an e-mail to them and ask them this question and also ask them if they'd like to help with the younger kids.

I hope you'll have some adult help with this - you cannot be expected to handle that many little ones by yourself and if they do expect you to do that - I'd stay home!
Get the older ones to help the little ones - set up a buddy system...

Duck Duck Goose is always fun.
Water Balloon Toss
Peanut on the spoon race
Marshmallow on the spoon races
Donuts on a string game
Make birdfeeders with pinecones, peanutbutter, and birdseed? Then you can leave them in the woods for the birds - or the bears - to find.
Make paperplate masks and have a parade.
Make puppets and have a puppet show - the older ones can plan it for the little ones.
Kickball is fun - even with little ones
Slip n slide... or a sprinkler or something to get wet if there is a hose available.
Get some books at the library or google children's playground games...
YMMV
LBC

Limbo! I played this with a bunch of kids recently (I used a jump rope, but you could use a long stick, whatever)...the kids had a blast!