Any ideas for a ladies member guest golf theme as opposed to golf format?

You could do better ball, where both players play out the hole with their own ball and the lowest score is taken. Scramble, where both players hit a drive, take the best one, both players hit the approach, take the best one, and then both hit the putt, take the best one. Foursomes, Player A hits the drive on the odd holes, player B hits the approach and so on, on the even holes player B hits the tee shot, and player A hits the approach etc. Or greensomes, where both players hit a tee shot, the best one is taken, whoever's tee shot is not chosen hits the approach and the rest of the hole is player out in alternate shots from there.