Question of the week:  Boran just won 100 gallons of fresh drinking water.  Why are they now going on a water run?  Top answers:
(1) Ethan decided to wash his hair.  Sadly, both the water and shampoo ran out halfway through.
(2) They decided the cooler clashed with their newly-painted mosquito nets in its current location, and decided to move it to the other side of camp. Since it was heavy, they dumped the water out first.
(3) They took turns taking showers under the open spigot.  Unfortunately, Big Tom went first.
(4) Clarence got thirsty.

Reward Challenge
Appears, based on clothing worn when accepting the reward, to be the obstacle course challenge.  We expect something along the lines of the heartwarming challenge we saw in S2, where Colby threw Jerri over a wall.  Now that was family entertainment!  We're assuming here that the reward is some sort of food-type-item, which is served to Boran, when they're standing on top of Lion Head Rock, near Challenge Beach (Fig. 3, below; the link takes you to Dan Bollinger's excellent Survivor Maps site - click on the IPIX on Lion Head Rock to compare it to the rock the Borans are on top of).  We say the clothes are the key here, because Ethan and Lex are dressed completely differently than in the construction challenge, which we think is IC.  The only positive correlation is that Tom appears to be wearing the same shorts (and no shirt) in both challenges, and on the mountain.  This would tell us, then, that Boran wins reward.

Immunity challenge
This challenge appears to involve carrying large quantities of both lumber (Fig. 6) and completed, box-like structures (Figs. 4,5).  They also appear to do some running (Figs. 2,3).  Some points of note here: There are only four members of each tribe shown.  Are the rest left to do something at the finish line?  Also, there does not appear to be any similarity between the stuff Frank is carrying and the boxes, so what's up with that?  Our guesses: the boxes are pre-made, and the lumber is for some other purpose.  Perhaps they have to run to pick up the box things, carry them somewhere, run back and get the lumber, bring it back.  They then either build something, or, because Mark Burnett really likes fire, perhaps burn their little forts.  Who wins?  Good question.  We think Frank and the lumber is near the end, and sicne he tells Lindsey, "Just go!",  Samburu may be lagging behind?  Or they could be winning.  But Samburu has three strong people plus KimP/Teresa, while Boran has four guys doing their heavy lifting.  Seems like a slight Boran edge.  Boran win?

Bonus note: In Fig. 1, Linda is facetiously thanking Lindsey, while the others look on, either mystified or disgruntled.  Lindsey's clothes match her IC garb exactly (although both KimP and Teresa are dressed differently than the front-runner in Fig. 2).  So it's probably IC day, but is this before or after IC?  If after, the downtrodden expression could signify a Samburu loss.  But that would seem too easy.  Probably before IC.

Boot
Here, we're still happy with either Clarence and Kelly from Boran, but we're guessing Boran wins immunity (for now), based solely on the highly suspect "Diane's Friends" putative spoiler.  From Samburu, Linda and Teresa stick out, since the AllRats purposely kept Frank around to help in challenges.  Insider clips from Ep.3 showed them mentioning both Carl and Teresa initially, then settling on Carl for the boot.  Also, Diane listed Teresa right after Carl in her list of friends, which might suggest Teresa came first.  But Linda is so over-the-top confrontational in the previews, and she grabbed so much screen time in Ep.3, that she seems more likely.  Also, if the "blue tribe" theory holds any water (and intro spec is the lowest form of speculation), Teresa needs to last until the "Twist" in episode 5.  We shall see.  We're probably wrong again.

Dead spoilers/spec: The "Boran loses four straight ICs" theory; theories based on Carl's lack of face time; "Carl grew a full beard and lost 40-50 lbs = late boot" theory.
Still-possible spoilers: (1) "The Blue Tribe" (Teresa, KimP, Lindsey, Lex - based on blue photos in opening credits), which goes hand in hand with...
(2) "The Twist" in Ep.5 putatively being a merge/redistribution into three tribes - splintering the AllRats.
(3) "Diane's friends" - list given by Diane in Final Chat of who she talks to: Teresa, Linda, Carl, Lindsey, Silas.  Sounded fake at the time, but Carl's ouster now casts this in a new light.
(4) "Carl's non-friend" (new!) - in Carl's Final Chat, he mentions he never really got to know KimP.  This would fit with the "Diane's list" of pre-jury bootees, all of whom presumably joined in on Diane's month-long safari as they were booted.  He also says he was surrounded by beautiful women, suggesting another woman takes the walk of shame in Ep.4.