If a barbarian is raging and he falls unconscious, does the rage end? Is it different if the barbarian dropped to 0 hit points versus due to a spell effect? Are there other conditions that cause raging to end?
Rages do not end when you go unconscious. Just about every other effect on a character does (damage dealing effects are an exception), but rages do not. This is largely due for balance as both rages usually come from daily powers and getting knocked out can make the powers that grant them underwhelming.