If you are arrested at an Occupy Event, call the National Lawyers Guild:
New York City: (212) 679-6018
Los Angeles: (323) 696-2299
Washington, DC: (202) 957 2445
Chicago: (773) 309-1198
San Francisco: (415) 285-1011
New Orleans: (504) 875-0019
Baltimore: (410) 205-2850
Minnesota: (612) 656-9108
Michigan: (313) 963-0843
Portland: (503) 902-5340
Boston: (617) 227-7335
Pennsylvania & Delaware: (267) 702-4654
Idaho: (208) 991-4324
Be very sure to write the applicable phone number in PERMANENT marker somewhere concealed on your body, protected from the elements. Do NOT assume you will be able to retrieve the number from a phone or a notebook. It is very likely you will be stripped of all your belongings.
(thanks to Joni Spigler)