Calvin and/or Alex can probably fill you in more... but basically anything that has to do with politics, elections, congress and congressional rulings, blaming the current president for everything (in about a year it will be somebody else). Abortion and religion are also very hot button topics. All three causes hot tempers and 'passionate' debate that devolve into name calling sometimes.
I think there used to be a unique set of rules listed on the old site but the FAQ and rules here are the standard 'boilerplate' rules that Alex hasn't updated or added onto.
I'm sure you'll get more responses also.