Lex Luther is left handed. When Clark is visiting Lex's memories, you see a younger "Alexander" painting a toy model with his right hand.
When Kara is listening to her music in the Talon, there is a close up of her MP3 player showing the time into the song is 1:25. In the four second close up the time doesn't change showing the music is paused. The next time you see the screen, as she is hitting pause, the music has advanced 10 seconds.