Have it packaged in something that cushions the fall, such as a box, with the egg suspended inside, in a net-like device. Or, as shown here:
It'll crack whether there's anything to cushion it or not.
Logically you can't drop it on to a cement floor without breaking it, unless there is something between that either slows the rate of impact or something to break it's fall when it hits.
Maybe like a yo-yo, attach a string to it, and gently lower it to the ground.
Concrete floors are very hard to crack!
I have done this, it amazes children. Wrap an egg with bubble wrap until it is about the size of a basketball, tape it up to keep it closed and then toss it up in the air and let it fall.