For starters, have you visited every major city in Europe, including historically famous cities, sites of historical battles, capitals of smaller countries? Sampled the local cuisine in each? Tried the local hobbies? Danced in a local club? Walked the Via Appia in Rome, visited the site of the "300 Spartans" battle against the Persians?

For closer to home, assuming you don't want to travel the world or you've already done that, I personally don't think I'd ever get tired of just enjoying life. Going to my favorite places, watching the city below from the top of a large hill, alternating favorite restaurants, continuing to spend time with friends, reading new books, and continuing scientific and intellectual pursuits.

If you want to discuss this further feel free to email me at jmorrow977@gmail.com.