Hi all. A question came up last night while playing that we couldn't find answer for (lots of beer had been drunk!)

Can you play a zero point card once you have used all your power, or must you have some power left? After trying to find out we decided you could play a zero point card until you passed.

No, he can't play even 0-cost cards anymore once his power marker is on the 0 space. Rulebook page 11:

"So long as a player has power points remaining, he may continue to summon a follower or play a card each time his turn comes. However, when a player’s turn comes and that player’s power marker is on the “0” space of his power point track, that player’s turn is skipped."

His turn being skipped implies that he has no opportunity to do anything anymore. Being on zero is equivalent to passing.

Thanks for the info! We were enjoying our beer a bit to much and obviously lost the ability to read

Not a problem, beer does that Even without it's often easy to misread rulebooks or misremember things for the first play.