Dendy is a Russian Famicom (NES) clone. You see, Nintendo did not sell their decks in Russia (as there is very little market there), but several clever importing pirates managed to get the parts that they needed and they made quite a decent business selling these systems, and pirate, hacked, and European games.

If you go to russia, supposedly no one has heard of the NES or Famicom, but if you ask if they have played Dendy, you will get a much greater response. These decks are rare collectors items, and are very valuable in the US.