Another time travel idea...
I want to be 20 again and spent a year at the Univeristy of Salamanca.
It's a college town and it feels it. The grocery store has a sushi bar and lots of cooked take away food and it looks like at least 50% of the people you see are young.
It would take a long time to visit every taverna and cerveceia in town and, due to a large contingent of international students, the bars promote various night for multi-language meet and greets and trivia.
And it's just beautiful, even on a cold and drizzly day.