Mehendi is something people do that are often from Bangladesh. They do it for weddings and dancing and other special occasions. It is also referred to as Henna
sometimes. Henna is the plant they use for Mehendi, and Mehendi is what they do. You can do it anywhere on your body, most popular on the hands and feet. The liquid is a brownish kind, but on your hand it turns out to be a orange red. It will darken when you wake up the next day, to a brownish red. You can do any design, but the people who do it for you in Bangladesh and other places, do it very good and just keep on designing some hardcore designs.
You should definitely try out Mehendi/Henna =)!