Question: things to do with used tires?
Answer: Build a castle, duh. Ok, technically this is called an "earthship," and it's meant to be an environmentally friendly way to build a house. ... 
Make flip-flops. ... 
Start an awesome garden. ... 
Build an obstacle course. ... 
Make furniture. ... 
Use them to get jacked. ... 
Create an outdoor staircase. ... 
Construct a wall or barrier.