Get on your bicycle and start paying attention to your surroundings. You never know what you might find. I was out walking one day, looked down and found a 14K gold chain bracelet. On this adventure I found a master lock, however there was no key so it is a useless piece of junk. I took it home and threw it away.
I live in an active housing development so there are other things that may be useful. You have heard the saying, one mans junk is another mans treasure. If you are near construction or a development, the 5 gallon buckets are always blowing off the trucks into the ditch. No need to buy one when you can get it for free.
Step 1: Stop and Listen to Nature's Lullaby
No matter how large the city you live in, you can find nature all around you. Stop and listen to birds chirping, frogs croaking or crickets singing. You get a free concert courtesy of nature. The best times to listen are 6AM-8AM and in the evening right around sunset. Now if you are an adventurous soul and willing to step into the forest, you can always find something in there singing to you just about any time of the day.
Step 2: Builders of Nature
All along my bike route, I can find fire ants. They captured my attention a couple years ago when my husband told me he noticed they build the mound higher right before a cold spell. When left undisturbed, they keep building higher and higher. I find a lot of them at the base of trees, along the underground power grid and next to the curb of the road.
Step 3: Nature's Tracks
The dirt will preserve the tracks of creatures who pass through on their daily journey seeking food and water.
If you have an imagination like I do, it's fun to guess what the creatures may be if the footprints are not easily identifiable.
Step 4: Nature in Flight
Every year in the fall and spring, these birds will bunch up together and quickly fly in and out of trees. I'm not sure if this is a mating or migratory ritual but it sure is interesting to watch.
Lots of ways to add fun to a daily bike ride.