This is not a question about what is on your bucket list, since I think of a bucket list as things you might actually do. But you could mention bucket list projects as well. To keep save-the-world mega-projects off the list for now, it should be a project you could do mostly yourself.
Do you want to build an autonomous solar powered boat to take you around the world, how about a solar powered aircraft, how about a completely self-sufficient off-grid dwelling complete with automated greenhouse, how about the ultimate gaming computer with an 18 core i9, or how about a full AI system to discuss politics with, or a robot to do all your chores for you.
Personally I would like to build a humanoid android robot just for the challenge of making it seem human, not trying to make it better than a human.
