Your little kid is going to get chickenpox anyway, so why not control when they get it by sending them to a playdate with a kid who currently has it so your kid can catch it?
Good idea, right? I mean it sounds logical. We all had chickenpox, and we already know it's easier on you when you're a little kid than it would be if you're adult.
So, pack the kids in the car, take them over to little Oliver's house and let them play together, sneeze on each other, etc, so your kid can get chickenpox on YOUR schedule.
Is it a good idea? Read this great article from parents.com to find out.