We don't have much to go on, but I thought it might be a good idea to start a thread on this.
On the SF spoiler page there is a picture from the Globe tabloid that SF feels is a water platform challenge. I tried to post the pic, but couldn't so here is the link:http://www.geocities.com/survivorfeverland/Spoilers.html
I think we've already seen these platforms on E1. I could be wrong, but I'm pretty sure these things had fires on them when the tribes were crossing the river for the fire challenge.
We also have these pics: (courtesy of ellipsiiis & paratrooper)
Jerri with immunity idol.
Keith and Liz watching and being cold.
The fact they are just watching may mean that they're already out of the running and waiting for the others to finish. The fact that they're cold may mean nothing. I checked the weather tracker and it's going to be nasty this episode.
http://members.tripod.com/avianado/ss2_weather_tracker_nov__1_thru_nov__15.htm#tc_7
We also have the S1 challenge list to use as a reference. Here's ferretkiss' S1 challenge sheet.
http://home.fuse.net/mel/SurvChallenges.htm
Here's where the speculation part comes in. We know that EPM keeps some of the key challenges the same, such as E1 & E6. I think E7 is another key challenge that EPM will keep. (or at least keep similar)
I remember the underwater challenge in S1, and I was thinking the whole time how unfair it was to the female contestants because men naturally have a larger lung capacity than the women. Well, duh, that's what EPM wants. Immediately after the merge the number 1 targets are the alpha males and this is his way of giving them a chance to remain in the game.
Using this reasoning, I don't think the challenge will be any kind of finesse contest and the major players will be Nick, Colby and Alicia.
Thanks to all the folks whose links and photos were included in this post.