We could harness energy from cars driving on roads through piezoelectricity, which is basically energy coming from compressing certain materials like quartz. The compression has to come and go; for instance if I put a piezoelectric crystal in my shoe to generate power, it would only generate power when I walk. If I was standing, it would generate no power.
This makes it perfect for roads; the cars constantly move and would therefore compress the crystals rapidly producing a decent amount of energy. I'm not sure of the extent of this power, but I'm sure it could be used to power lights on the side of the road at least.
Reward: The first such road being dedicated to my name.