Both these designs 71 and 72 are clever and eye catching. for some reason the squared circle element looks vaguely familiar and might be too close to an Australian company (maybe a bit too macquarie bank), though the balance and depth looks very cool. I think #70 is intriguing and has the right feel to it. I like that both designs have the venue and date clear and relatively easy to read from a computer screen. without getting too complex, would changing the colours on the two theme words make it grab the eye a tiny bit more?