This word is derived from Nintendo, a well-known video games manufacturer whose name is synonymous with video gaming.
Often referred to as a disease or medical condition.
Note that this word does not refer exclusively to Nintendo video game products.
Person B: Mostly cash.
Person A: Really? What did you buy with it?
Person B: I came down with a nasty spell of Spendtendo and bought a Wii, an Xbox 360, a PS3, a DSlite, a bunch of games, and shirt that says "all your base are belong to us."
Person A: Wow. I wish I had that kind of money, not to mention time.