I think the entire universe of potentially unethical behavior by judges and lawyers is pretty broad, which is why we operate by so many ethical rules. Most lawyers here on avvo.com will be better equipped to tell you whether a particular behavior is unethical, and are more likely to answer that question than give you a myriad number of hypothetical examples of unethical behavior, which might not even apply to your situation.
But, if you're interested in an academic exercise, here is the canon of Judicial Conduct for New York judges: http://www.nycourts.gov/rules/chiefadmin/100.shtml
Most judges are lawyers, so they would also have to abide by the New York Code of (Lawyer) Professional Responsibility (http://www.law.cornell.edu/ethics/ny/code/NY_CODE.HTM) but note that a judge isn't an advocate, so many of these rules are inapplicable in a judge's official capacity.
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