You need a building that can be darkened completely inside (or is sufficiently dark inside at night). The darker it is inside, the more fun the game is. The referees should have a flashlight at hand (or be able to turn on the lights), just in case.
All participants except the "seeker" hide in the completely darkened building. The more players participate, the bigger the building needs to be.
The seeker (called Dracula here) then searches for those players. To induce a fitting atmosphere, he may do typical Dracula-like sounds. When he can find a hidden person, either this person is out of the game OR it becomes a Dracula, too (decide that before the game).
Winner of the game is the person that has found the best hiding place and is found last.