My son, 6, is attending a summer day camp where some of the older kids play Chrononauts during lunch. After watching for a few days, he finally played the Artifaxx variant with them last week. That afternoon, he came home saying, "I played the coolest game ever! It's called Chrononauts! Can we get it?"
We picked it up and played our first games together today. It was a hit. I had previously gotten Aquarius and Family Fluxx, and he liked Fluxx, but said that Chrononauts is way cooler. (Maybe in part because the cool older kids play it.)
Looks like we've got another favorite on our hands!