Beer pong battle ship hack - AWESOME! take a shot when a ship is sunk. dear god.
Messy twister with shaving foam food dye. Ok, now this is FUN! I might not do this with little kids but teens and adults would be rad.
Jungle Juice, Hooch, Boobie Juice, Hunch Punch - whatever you want to call it
Yard twister - love for spring and summer. Could use food color and water for snow in winter.
Best Homemade Slip & Slide for adults. Ever! Make sure you've got a slope & enough water. Fun, fun.