If you're lucky enough to visit during festival time, you're in for a treat. Two of the biggest in Delhi are Diwali, the festival of light, which celebrates the triumph of good over evil and is marked by thousands of candles and lamps; and Holi, the festival of colors, a celebration of hope where people throw colored powders made from medicinal herbs over each other and drink thandai, a refreshing cannabis-laced drink.
Some cities are plagued with pigeons; Delhi's influx of sandwich-snatching rhesus monkeys rampage around the government areas of the city (and occasionally destroy top-secret documents in the process). Look out for the langurs (larger black apes) brought in to scare off their simian cousins.
The Delhi climate is one of extremes, ranging from sweltering heat and humidity in the summer to near-freezing temperatures in winter. It's also one of the world's most polluted cities. To handle the environment, stock up on sun block, mosquito repellent and asthma inhalers before you go.
If you do go in winter, make the most of "Dilli ki Sardi" -- the famous cold of Delhi. Muffle up in warm clothes, imbibe some hot tea and enjoy the spicy Indian food, which tastes wonderful in the cold. If you go in summer and the heat gets too much, do as the locals do and escape underground to the air-conditioned metro.
Delhi's sporting passion is cricket. Catch the first-class Delhi cricket team at Feroz Shah Kotla, a ground that has seen some historic performances including Indian leg spinner Anil Kumble's magnificent 10 wickets in an innings against Pakistan in 1999.
If the weather gets sticky, quench your thirst with jal jeera, a cumin-spiced Indian lemonade or, if you fancy a bit more of a kick, try a rum and Thums Up (Indian cola).