In addition to playing Japanese card games such as Pokémon and Yu-Gi-Oh, kids love to think they know something about collecting and trading the cards themselves.
This can be an expensive pastime - made worse if the child spends allowance or birthday money on a card that turns out to be fake.
On Friday, U.S. Customs and Border Protection officers seized 33,000 counterfeit sets of Pokémon, Yu-Gi-Oh and Zexal cards that had been shipped to the Los Angeles/Long Beach seaports from China.
Had they been sold at regular retail prices, the cards would have gone for a total of $218,000. If unsuspecting kids and parents had paid more, thinking the cards were collectible, the haul for the counterfeiters would have been even higher.
"Most parents are unaware they are buying a counterfeit product," the border patrol said in a statement.
The agency said that seizures of counterfeit items had increased 24% in 2011 over 2010, the latest full years for which data is available.