It's LOST Eve(a) because in just over three months time, we will refer to the eve of LOST's series finale as "LOST Eve."  I don't have anything else to add.  I just wanted to make sure that everyone realized that tomorrow is amongst the biggest days of the year, perhaps only being surpassed by LOST's finale.  I will be making a post every Wednesday-ish after the Tuesday night episode.  Look for those, but don't read them if you haven't seen the episode yet.