Here's a look at tonight's sci-fi TV:
Fringe, 'Over There Part 2' -- Olivia and Walter continue searching for Peter in the alternate universe in the second half of the season two finale. As the two worlds come closer to colliding, they soon learn that saving them will require some heavy personal sacrifices. (9 p.m. ET on Fox)
FlashForward, 'Countdown' -- There are only two episodes left until we can move on and pretend like FlashForward never happened. (I'm sure ABC would like nothing better.) For those of you who still think the show will offer a satisfying conclusion that answers all of the series' questions, well, you're just crazy, and come next week you'll be angry, frustrated, a little sad, and still crazy. (8 p.m. ET on CBS)
Head after the jump for promo clips.