Possible Clues:

• Simple card game, and what's hidden in the answers to starred clues
• Popular card game
• Kids' card game
• Fast-paced card game
• Goofy card game?
• Card game that literally explains this puzzle's circles
• Uno ancestor, and, in a way, what are hidden in 17-, 28- and 45-Across
• Game on which Uno is based