I get really annoyed when I see people writing about peaking someone’s interest.
A mountain is peaked. A cap can be peaked.
People can even look peaked: in this sense, it means they are pale.
A career can peak.
In fact, someone’s interest in something can peak, right before it declines again.
While they sound the same, the correct term for having caused intense interest or curiosity, is piqued.
To pique someone’s interest is to heighten or arouse it. In other words, it is to stimulate their curiosity or attention.
A fit of pique is an episode of annoyance or irritation – such as might happen, for example, if someone’s negative emotions are piqued.
A related word is piquant, which means provocative, tantalising, spicy or tangy. Food that excites the taste buds or a story that excites the imagination can both be described as piquant.
The other homophone is peeked. This is the past tense of peek: to take a quick look, or a sneaky one.

So… now that I’ve piqued your interest with my fit of pique, and you’ve peeked at my post… I’m sure your interest has long since peaked.
See? Homophones can be fun!