Hint - "GO" Collect Zack Dollars
The pool hopping mini-game is now tougher, so you may despair at the high price tags in the Sports and Accessories shop. However, head for Nikki's Marina and participate in a jetski race (you get a free machine once you start a vacation).

It's not terribly hard and as long as you can finish first in two laps, you get a mild sum of Zack dollars per time segment.
Easter Egg - Pole Dance
Unverified. A 1000 Zack Dollar (x3) bet (and only that sort of bet) on Christie's "Poison Dancer" slot machine will unlock succesively longer segments of Christie's pole dance scene. A jackpot incidentally gives you a cool 3 million for each hit as well.