Before class, choose a class member that would be comfortable being blindfolded during class, but don't tell the class member before hand. Invite a parent of the class member you chose to visit the class without letting the class member know.
Also invite a member of the ward to visit the class who doesn't know the class member.
Have both invites remain outside the classroom until you call them in. Have the class member come to the front of the class and blind fold them. Tell them you want them to identify the visitors without seeing them.
Invite the parent into the class and have the parent greet the class member. The class member should easily recognize this visitor.
Next invite the other visitor in to greet the class member still blind folded. Hopefully, the class member cannot recognize the 2nd visitor.
Take the blind fold off and invite the class to discuss why the class member could identify the first visitor and not the second one. Point out that the class member communicates with the first visitor daily, but hasn't communicated with the second visitor at all.
Teach that we cannot recognize our Heavenly Father or have a relationship with him if we don't have daily communication with him. Sometimes it's fun to use 2 or more class members for this attention-getter. You can maybe even use this for creating a better relationship with your family.