Casltewars is a turn based card game where your goal is to be the first to build a 100 storey castle, you also win by destroying your opponents castle.
(to discard cards hold down the Ctrl button)
Castlewars is a clone of the game Ants made by Miroslav Nemecek. his homepage is gemtree.com but sadly ants is no longer hosted there but if you use google i am sure you will find it :)
and yes as many of you have pointed out this game is based on Arcomage from Might and Magic. i dont get it why are so many you so mad about it?