The vapor from e-cigarettes may be hard to spot, but supporters of the devices will be anything but unseen this weekend.

Russ Wishtart, a plaintiff in a suit against the city over its law to ban e-cigs from restaurants and bars, is organizing a "Vape-In" Saturday at the Arsenal in Central Park. Wishtart said the ban, which went into effect last week, is "immoral, unjust and downright stupid" since the devices don't emit secondhand smoke.

"The last thing that NYC wants to do is write tickets to individual vapers," he said in the notice for the rally. "They want bar and restaurant owners to do their dirty work for them, just like they did with the smoking ban."

The devices are not regulated by the government, but some studies show that they can be harmful to a person's health.