When you peek at something, you're doing something you shouldn't be doing. A good way to remember this is to think of the ee in the word peek as two eyes looking at something.
Scotty peeked at his Christmas gifts in the middle of the night.
Pique comes from a French word, and it means to excite.
The odd-shaped package piqued Scotty's interest.
A peak is a real or metaphorical pinnacle or high point.
The package marked the peak of excitement for Scotty.