I've watched the first few episodes of Battlestar Galactica, and a friend recently got the game. We love The Resistance, and I'm eager to try a similarly deceptive game with more going on than just deception. But, I don't want to spoil the suspense of the TV show. Do I need to watch more before I play the game?
(Very) broadly speaking, the base game spoils Season 1, Pegasus spoils Season 2 (and the start of Season 3) and Exodus spoils Seasons 3 and 4.
At least one exception to this that I can remember is that one Pegasus character's card spoils an event in Season 4. (Spoiler follows)
Having said that, I've played with multiple people who were watching the series at the same time. As long as you're roughly half-way through the first season, you should be (mostly) fine for the base set (as long as you don't read too much flavour text!). I'd hold off on the expansions until you've seen a lot more though.
The base game contains several spoilers that are not completely revealed until you finish the first season, and a couple of episodes into Season 2. If you have watched the mini series, and the first disk of Season 2.0 you will be.fine.
The Battlestar Galactica expansions contain spoilers that go well into the 4th season.
As for some specifics (SPOILERS)
Cylon Sympathizer card image, Helo character card, Adama is an Admiral....
Yes. I will not link to specific examples because that would defeat the purpose of not spoiling, but the the Crises cards encountered, character abilities,and still-frames chosen to illustrate the cards contain major spoilers as to events, identities, and loyalties of various characters.
Once you have seen all of Season 1, you are clear to play the base game. I don't remember how far in the series the Pegasus and Exodus expansions span.
The best you can do is to say that a game will be "minimal spoilers" as opposed to "no spoilers". Problem is, someone who's more perceptive in observation and putting two and two together will notice things that give away plot points, personalities, and situations from the various cards. Hell, many of the crisis cards depict struggles in the TV show, with some of them the actual names or the main plot of the episodes themselves. Even just looking at the box front, backs, and reading the game description will do that too!
If you want to reduce the # of spoilers, have everyone watch at least the miniseries before playing the base game. Otherwise:
mini-series = decent chunk of the base game
season one = roughly base game. Do NOT read flavor text in this case!
Season 2 = Pegasus
season 3 = Exodus
Season 4 = Daybreak
Note though that some of the stuff does spill over, hence the "roughly". For example, there was probably a crisis cards in Pegasus that was actually a season 3 occurrence.