In Trout's novel, the aliens give the two Earthlings a fake stock market ticker.
They tell the Earthlings that this is connected to the stock markets back on Earth, and that they now have a million dollars in investments in the market.
This is all a lie: the aliens just want to make the Earthlings perform for them in their zoo.
But the humans think they are making a ton of money back on Earth.
They also try religion: when they have a bad week on the market, they give prayer a whirl.
It seems to work, too: their fake stocks go up after they pray.