The cardboard-boat myth was pretty interesting. As usual, it was a variation on past Mythbusters stories, but they haven't done cardboard boats before, and there were some very clever solutions to making the cardboard strong and watertight using only the permitted materials. Although, as usual, the "individual" mini-myth involving shooting blindfolded was cursory and incidental.
On the "reality"-show front, I'm a bit surprised at how it went. I'd gotten the sense that Hackett had been cast in the designated-heavy role, the guy who went his own way and created tension by not being a team player, but this week, his team got along totally smoothly and it was the other team that was failing to cohere. As usual, it was pretty easy to predict who the sacrificial victim would be, both from his isolation on the team event and his bad gun handling (although, as always, it's hard to trust the reality and non-staged-ness of anything in this kind of show -- how do you hold a gun in a way that makes it jam, anyway?). There was probably just as much of a case for ditching Tracy, but no way are they gonna drop the sexiest woman this early in the show.
Playing along for the moment with the premise that these contestants might actually go on to be Mythbusters in a new series, I'd say Allen is a keeper. He's got the same kind of energy, wit, and sense of fun as Adam. Not sure who else I'd pick, though. I'm definitely inclined to favor Tracy because she's hot, and I think she's got a fun delivery and personality. Martin comes off as really competent but a bit vanilla. Hackett is a colorful presence, but I haven't warmed to him, though he was more likeable this week, when he wasn't presented as the troublemaker. Brian seems skilled and effective, but a bit too much of a Jamie clone in appearance. I have no preference either way regarding Jon and Tamara.