Learn to make clothes. Design and create seasonal "uniforms" that are versatile and can be worn every day.

Develop a niche podcast. Become deeply familiar with the domain.

Design and build a small, rustic country home. Ski chalet, mountain home. Simple.

Develop a new variety of a plant. Tomato, cannabis, a flower. For beauty or for regional adaptation

Assemble a simple small plane. Take flight!

Design a backyard pavilion / gazebo / shade structure. Do the build as well. Incorporate electrical and water if possible.

Learn electronic music production. Record an album and play a live set.

Develop a new sport. Come up with a new game, sport, fitness activity.

Build a sculling boat. Learn about all the engineering and mechanics. Travel around to take the boat out on different lakes and rivers.