This I can answer, a day late and a dollar short. She was driving in the season primere to find out what happened to her cousin Chloe, who had supposedly been blown up in the finale of season four. She gets lost and has car trouble, and she pulls to the side, when this huge, like, fireball falls from the sky and crashes into the corn field. She drives to check it out, and finds Clark (or Kal-El, really) stark naked standing in the middle of a burnt out circle in the cornfield.
And the hilarity ensues. She was easily the best written character of season 4.
Have not watched season 5 to see if this continues.