Ringworld

Any book that begins with the main character teleporting to different time zones in order to prolong his 200th birthday party is worth giving a chance. And while Ringworld doesn't exactly live up to its intriguing opening, it's still a fun read with its share of interesting ideas and characters. The most interesting of those ideas is the titular Ringworld, a colossal artificial ring orbiting a distant star. The architects of the Ringworld and their purpose in building it form the central mystery of the novel, although the shallow characters and improbable circumstances threaten to overshadow it.