I do sort of agree with you, they've really ran out of worthwhile myths and are mainly doing... nothing, really. Like you said, the green hornet episode was terrible. Hey, I'm Seth Rogen, listen to my annoying laugh, uh huh huh huh huh. Oh, yeah, and we've totally carefully chosen a small amount of explosives that shouldn't completely destroy the front end loader... 250 pounds worth of explosives, it'll definitely stay in one piece! But they're inconsistent, some of the episodes are still quite good - namely the episodes that don't end in "well, we've completely busted the myth and still have a half hour left, let's blow a hole in the clouds!"
For what it's worth I don't download the show and Discovery Canada is always some three months or so behind.