Gori is best known as the birthplace of Joseph Stalin, and the Stalin Museum dominates the town both physically and culturally. Whether or not that appeals to you, it is one of the more unusual museum experiences in the Caucasus — a grand Soviet-era building constructed around the tiny house where Stalin was born, filled with photographs, personal effects, and his private railway carriage.
Above the town, the Gori Fortress (Goris-Tsikhe) sits on a rocky hill with views across the valley. The current walls date mainly from the Middle Ages, though the site has been fortified since antiquity — Pompey is thought to have taken it in 65 BC.
The cave city of Uplistsikhe, about 15 km east of Gori, is one of the oldest urban settlements in the Caucasus, carved into a rocky hillside above the Mtkvari River. It flourished from the 1st millennium BC through the medieval period and is well worth the short detour.
Gori is an easy day trip from Tbilisi, about an hour by minibus.