Warhol, “Liz #3 [Early Colored Liz],” 1963 Presale estimate: in region of $30 million Photo by Lee RosenbaumIf you’re planning to attend this week’s big contemporary sales (tonight at Sotheby’s; tomorrow night at Christie’s), whether in person or online, here’s my CultureGrrl Video with a few highlights to get you in the mood to spend your multi-millions (or maybe not):