Read books . In fact, I am reading everyday, because it is very easy to insert a piece of reading time to your daily schedule. If you have ~$20 lying around and don't mind sending an hour writing addresses, send postcards to friends away. If you don't have friends away, try postcrossing .
Let me simply make a table you can consult:
Cook some ribs
🔳 Mount Mountain Fuji, enjoy the sunrise. 🇯🇵🗻🌄 🔳 In an Indian cinema, watch a Bollywood movie. 🇮🇳🎬🍿️ 🔳 Standing on the very bridge in Cambridge, read aloud the poem “Goodbye Cambridge." 🇬🇧📃 ⬜ Get graduated with a PhD degree! 🎓🏫👩🔬⚛ 🔳 Make it rain at a casino in Las Vegas. 🇺🇸🎰💰 ⬜ Safari across Africa. 🌍🦁️🐾🏜 ⬜ In a Tianjin teahouse, hold a stand-up comedy talk-show with Guo Degang. 🎭🍵 ⬜ To the summit of Mount Everest, to the deepest seabed, to the North and South Poles or to the outer space. 🌌 ⬜ Write a book. Sell at least 500 copies. ✏ ️📖🖨️ 🔳 [4 words omitted] before adulthood. ⬜ Enjoy an opera at the Sydney Opera House. 🇦🇺🎭 ⬜ Visit Damascus, Jerusalem, Masyaf and Acre. 🇸🇾🇮🇱 ⬜ In Pyongyang, present a bouquet of flowers as every foreigner do. 🇰🇵💐 🔳 Collect a full set of Apple devices. 📱💻⌚️🖥️ ⬜ Ride a horse in Mongolia. 🏇🇲🇳 ⬜ Play soccer in Brazil. 🇧🇷⚽️ ⬜ Star in a movie, TV series or release an album. 🎼🎥🎞 ⬜ Ride a camel in Egypt. Admire the pyramid. 🇪🇬🐫 ⬜ Take a hot air balloon ride in Turkey. 🇹🇷 ...