Then here's a new one:
"I find it helpful at times like these to remind myself that our true enemy is Instinct. Instinct was our mother when we were an infant species. Instinct cuddled us and kept us safe in those hardscrabble years when we hardened our sticks and cooked our first meals above a meager fire and started at the shadows that leapt upon the cavern's walls. But inseparable from Instinct is its dark twin, Superstition. Instinct is inextricably bound to unreasoning impulses, and today we clearly see its true nature. Instinct has just become aware of its irrelevance, and like a cornered beast, it will not go down without a bloody fight."

Secret of Monkey Island?

Nope. IIRC, that was "Never pay more than twenty dollars for a videogame."
My quote plays during the end credits of a totally different game. It is one of the games available on GOG.

I thought that would be too easy... also, I thought the monkey island quote was something else, but couldn't remember.

Serious error on my part! I just went back and listened to the quote again. It's SUPPOSED to read:
"You've just spent sixty dollars for a videogame that ended. A LONG TIME AGO. Fool! Sucka!"

Heh duke nukem manhattan project?

Some A-team/Mr. T game?

Since it's been up for so long and no one has guessed it, I'm just going to tell the solution: it's from Jack Orlando's intro, where Jack says it to his acquintance.

Nope. We have those on GOG?
Mmm. Never played that one. The bad reviews turned me away...

I don't know if they exist at all, I was just guessing.

No. That one was "I pity the fool who paid 60 dollars for this game!".

Ok, I'm doing a new quote.
"TIMMY!"

South Park O.o?

Would that be the crappy N64 South Park game?