You could do a challenge that requires a little thinking or a small calculation on the part of the player, but to hit the multiplier will be easy. Steve used to do these but they were pretty hard , you could do a simple one. A few examples are:
a) Go to the casino home page, find the sixth game counting from left to right, find 4 completely visible multipliers, add them together and hit on the same game a multiplier above that total.
Answer: Plinko, (2.4x+2.6x+3.5x+4.9x = 13.4x), so first one who posts a hit of 14x and above on Plinko wins
b) Go to the casino home page, find the eigth game counting from left to right, 5 red numbers are visible, add them together and hit that number on the same game 2 times consecutively
Answer: Roulette, (1+3+5+7 = 16), so hit 16 two times consecutively on roulette