On last weeks Ask JTF show a member by the name of chicagoJew asked about Jewish excommunication. Chaim correctly responded that Judaism has such a concept which is called 'Cherem'. There are many laws involved with this process, many from the Talmud, and it is not used often today.
First here are the mentions of Cherem in the Talmud:
http://www.webshas.org/baisdin/punish/cherem.htmCherem/Shamta/Niduy - Forms of Ex-CommunicationProcess of Ex-communicationWarning for the party before ex-communication: Moed Katan 16a
By a summoned party who refuses to show in court, the ex-communication includes mention of the name of the Sage involved, and uses the language of "Cherem": Moed Katan 16a [See Rashi "UMacharimin"]
Blowing of a Ram's Horn: Moed Katan 17b
A bill, known as a "Peticha": Rosh HaShanah 31b
Beginning or Continuing a period of ex-communication through the Intermediate Days of Holidays: Moed Katan 14b
Whether "Niduy" is equivalent to "Shamta" or not: Nedarim 7b
Duration of the "Niduy" brand of ex-communication: Moed Katan 16a
Duration of the "Shamta" brand of ex-communication: Moed Katan 16a
Duration of the "Nezifah" brand of ex-communication: Moed Katan 16a
Duration of modern "Nezifah": Moed Katan 16b
Duration of "Nezifah" by the Jewish Leader: Moed Katan 16b
Differentiating durations for different types of ex-communication in Israel and Bavel: Moed Katan 16a-b
Considering part of the last day of ex-communication to be like the entire day, to end the period early in the day: Moed Katan 16b
Self Ex-Communication: Moed Katan 17a; Nedarim 7b
Ex-Communication without the presence of the subject: Moed Katan 17a-b
Ex-communicating someone before one's teacher: Eruvin 63a
Rescension of Ex-CommunicationEx-communication requires rescension even if it is conditional, and the condition does not come true: Makkot 11b
Rescension can follow the ex-communication immediately: Nedarim 7b
Rescension of the "Shamta" brand of ex-communication before its automatic 30-day period: Moed Katan 16a
Rescension by a party who was not involved in the original ex-communication: Moed Katan 16a
Whether each individual involved in the ex-communication rescinds his own portion, and what happens if one of them dies before the time for rescension: Moed Katan 16a
What to do if one doesn't know who ex-communicated him: Moed Katan 17a
For a Torah Scholar to revoke his own ex-communication of himself: Moed Katan 17a; Nedarim 7b
Whether rescension of an ex-communication which was performed before a certain Sage, requires his presence for the rescension as well: Nedarim 7b [2x]
Requiring 10 people [and what type of people] for rescension of certain types of ex-communication: Nedarim 8a
Seriousness and Power of the Ex-CommunicationThe word "Shamta" implies Death or Desolation: Moed Katan 17a
The Numerical Value of the word "Cherem" implies that ex-communication affects all 248 limbs of an individual: Moed Katan 17a
Considering Ex-Communication to be more severe than Whipping for Violation of Rabbinic Rulings: Pesachim 52a
Considering ex-communication to be more severe than a straightforward prohibition: Niddah 13b
Whether a Sage must abide by an ex-communication declared by his Student, and the Student by that of the Sage: Moed Katan 16a, 17a
Whether an ex-communication extends to other towns as well: Moed Katan 16a
Whether an ex-communication by the Leader of the Jews holds for all Jews, and the reverse: Moed Katan 16a
Power of a student who ex-communicates specifically for his own honor: Moed Katan 16a, 17a
Uses of Ex-CommunicationFor a person who refuses to answer two Court summonses: Moed Katan 16a
If one hears another person use Gd's Name in vain: Nedarim 7b
For a court which acts improperly: Nedarim 20a
Use of the levels of "Cherem" and "Niduy" for one who refuses to answer Court Summonses: Rosh HaShanah 31b, Moed Katan 16a
Multiple ex-communications for one who insults Torah Scholars: Moed Katan 16a
For arousing the evil inclination: Niddah 13b
For one who causes himself to have sexual thoughts: Niddah 13b
To force a Damager to travel to Israel with the Victim, to pay the Fine: Bava Kama 15b
For someone who breaks a Rabbinic Law: Shabbat 130a; Kiddushin 39a
For speaking ill of a deceased Torah scholar: Berachot 19a
For someone who takes ritual hand-washing lightly: Berachot 19a
For someone who calls someone else an Eved: Kiddushin 28a
For addressing Gd arrogantly in prayer: Berachot 19a
For someone who maintains a dangerous item in his house: Bava Kama 15b
For someone who works on The Day Before Pesach after mid-day: Pesachim 50b
For someone who travels on the Second Day of Holidays in Exile: Pesachim 52a
For someone who misquotes a Torah lesson: Bava Metzia 47a
For improperly giving people roasted meat on Pesach night: Pesachim 53a-b
For working while there is a Corpse awaiting Burial in town: Moed Katan 27b
For a person who is about to perform a rabbinically prohibited act on Shabbat: Eruvin 63a
For people who stop attending a class: Kiddushin 25a
Ex-Communication of a Torah Scholar about whom bad rumors abound: Moed Katan 17a
General ex-communication of Torah Scholars: Moed Katan 17a
One should be wary of placing Torah Scholars in Ex-Communication: Pesachim 52a
Ex-communication of Barak on "Mayroz," who was either one of Sisra's leaders or Sisra's Mazal: Moed Katan 16a
Insitution of the Court in Usha preventing ex-communication of a Chief Justice who sins only once: Moed Katan 17a
For failure to honor the Torah and its scholars: Berachot 19a
For disagreeing with the majority in a matter of law: Berachot 19a [see Rashi "medameh"]
Treatment of the Ex-Communicated PersonA large stone is placed on his coffin if he dies under ex-communication: Berachot 19a; Moed Katan 15a
Effect of ex-communication on those who eat/drink/associate with the ex-communicated person: Moed Katan 16a
Publication of the ex-communicated person's sin in his town: Moed Katan 16a
Behavior of the Ex-Communicated PersonFlogging for remaining in ex-communication for 30 days without attempting to get it repealed: Kiddushin 12b
Shaving: Moed Katan 15a [2x]
Laundering: Moed Katan 15a [2x]
Wearing a covering over his head: Moed Katan 15a
Wearing Phylacteries: Moed Katan 15a
Greeting others: Moed Katan 15a
Learning Torah: Moed Katan 15a, 15b
Hiring a worker, or being hired: Moed Katan 15a, 15b
Differentiating, for business and for learning Torah, between one in the "Cherem" category and one in the "Niduy" category: Moed Katan 15a
Tearing his clothing: Moed Katan 15a; Bava Metzia 59b
Overturning his bed: Moed Katan 15b
Sitting on the floor: Bava Metzia 59b
Going to work: Moed Katan 15b
Bathing: Moed Katan 15b
Wearing [leather] shoes, on the road or in town: Moed Katan 15b; Bava Metzia 59b
Sexual relations: Moed Katan 15b; Nedarim 20b
Sending Temple Offerings via proxy: Moed Katan 15b
"Ex-Communication from Heaven"One who is unmarried, or married without children, or who has children and doesn't raise them to learn Torah: Pesachim 113b
One who does not wear Phylacteries and Tzitzit-Fringes, and have a Mezuzah-Scroll on his Doorpost: Pesachim 113b
One who doesn't wear shoes: Pesachim 113b
One who doesn't take part in a Meal of a Mitzvah: Pesachim 113b
Adam creating demonic spirits with seed he accidentally wasted during his one hundred and thirty years of ex-communication: Eruvin 18b
Implementation of "Ex-Communication from Heaven"Wearing a covering over his head: Moed Katan 15a
Greeting others: Moed Katan 15a
Sexual relations: Moed Katan 15b
Sending Temple Offerings via proxy: Moed Katan 15b
Specific ex-communicationsRabbi Eliezer: Berachot 19a; Shabbat 130b; Bava Metzia 59b; Niddah 7b [acc. to Rashi]
Interesting Expressions for forms of Ex-Communcation"Berachah": Bava Metzia 59b
"Stand in your place": Yevamot 105b
"I don't recognize you": Moed Katan 16a
"Is someone calling you outside?": Moed Katan 16b
"Go (tell them to) stay indoors": Kiddushin 25a
"Cast sparks of fire [pulsa d'nura] into your face": Bava Metzia 47a