As of 02/06/2011, Invigorate is banned in peasant tournaments in Groningen.
We realize this banning comes short after the March bannings, but we did put Invigorate on the watchlist then. After only two tournaments we have to conclude that Invigorate is simply too strong in infect decks. Yes, an infect deck is still beatable, but you have to have a one-mana answer, because they can kill you on turn two. Black has good options that fit in black deck's strategies, but other colors aren't as fortunate.
We believe that, rather than let the metagame warp itself around these super-aggressive infect builds, it's better to eliminate the worst offender in the deck. This will slow down infect decks by a turn or two and give other decks the room to be somewhat more inventive with their answers.
To see the full list of banned cards, click here.