1. If you roll a 1, you grant combat advantage to all enemies till the start of your next turn. You also get to use the magic d20 afterwards. It does not have a 1. You can use it till the combat is over, or another player rolls a one. Then they get a “blue ring of shame” and the magic d20.
2. You may use an action point once in an encounter to re-roll if you miss on a daily power. You may also use an action point in that same encounter.