Divide up into teams, there needs to be 2 or more teams with at least 2 people on a team.
Each rider gets a spoon and each team gets one egg.
One person gets the egg, rides across the chosen distance and back at a walk and hand the egg off to the next persons spoon on your team.
The first team to have all their riders finish the chosen distance & back wins.
I suggest using either a hard boiled egg or a plastic easter egg to avoid any messes.
This game helps with kids (and adults) who are fussy with their hands, it helps them to steady their hands especially.
I think the slight competiton really makes it fun for the kids this is a pretty easy game. Riders that cant quite ride on their own or have a horse that isn't cooperative might need a helper to guide them.
You can make up your own ideas on what happens if you drop an egg but at my barn if you drop it that rider goes all the way back and and gets a new one, and they need to walk instead of riding!