Case set instructions.
Enter in the code from your K'NEX Building Set Instruction Book...
 

Combo builds.
Combine parts from your Building Sets to create cool "Combo Build" models!
Select a Set... 20 Model Set with Magnets Super Structures 50 Model Building Set Light-Ups 30 Model Building Set Wheel Action 10 Model Building Set Fun Rides 10 Model Building Set Speed Machines 10 Model Building Set Designer's Choice 30 Model Light-Ups Creative Building Combo Pack Builders Fun Combo Pack Cool Construction 10 Model Building Set Free Fun Rides 10 Model Building Set Racers 20+ Model Building Set Semi Truck Pick-Up Truck Dump Truck Tow Truck