Navruz — the Persian New Year — falls around March 21, the spring equinox, and is the biggest celebration in Tajikistan. Dushanbe's public spaces fill with music, dancing, traditional games, and food. The celebrations at Dousti Square and Kohi Novruz are the most organized; the spontaneous street parties in the parks and residential neighborhoods are often more fun.
Traditional Navruz foods include sumalak (a sweet paste made from wheat sprouts, cooked communally overnight) and samanu (a similar sweet). Traditional games include horseback sports, wrestling, and the giant rope-swings (arjang) set up in parks across the city. If you can time a visit to Dushanbe for Navruz, it's worth prioritizing.