Murder
Molestation
Rape
Manslaughter
War Crimes
Indentity Theft
Assault
Breaking and Entering
Drunk Driving (not necessarily a jail sentence first offense, just probation
Adultery (shouldn't even be against the law)
While I agree with you in the fact that Adultery shouldn't land one in jail I certainly think it should be taken into consideration in divorce, custody, child support cases.
It can be used as a bargaining chip I suppose to appeal to the human feelings of an impartial arbitrator ruling on the result of a divorced marraige. But it shouldn't been seen as against the law.