Twice in the last week I've seen "peak" used where the user meant "peek." That's right, you "take a peek" at something, you don't "take a peak." I thought it might be because the usage of "peak" is at its peak now (or at least is peaking). So I googled peek and peak and found the theory supported.
Habits of thought: when we think the sound that's made by the word "peek" or "peak" we first think pitch and pinnacle, the top of the game. "Peak" is part of the vocabulary of the technologized corporate workplace: "peak performance," for example, is a precise term of art with a powerful analogical afterlife.
"Peek," on the other hand, is modest and unassuming, sometimes clandestine, usually timid. At best, it is not a thorough inquiry. You don't make your numbers by taking a peek at the competition.