These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Canon Discontinuity: The only Oh Yeah! short not to be shown on the show proper, "Chalk Rain". Also notable because it featured a fact about Chalkzone that never was mentioned again: the rain in Chalkzone is the chalk sidewalk drawing being washed away... by the rain.
Despite this, a clip of it still appears in the intro.
Ear Worm: The theme song, by far. To a lesser extent, the Accordion Worm song.
The 1-minute music video songs run a close second.
Skrawl's song. After two or three variations of it, it will never leave your head.
Buttercup, one of Elizabeth Daily's most popular roles, has an episode where she destroyed the chalk of her sister, Bubbles. This becomes ironic in ChalkZone, where Rudy Tabootie, who is also voiced by Daily, pretty much has chalk as his main weapon.
Vindicated by History: When it was still running, ChalkZone was despised by a lot of older Nickelodeon fans. These days, you will find much more fans than haters.
We're Still Relevant, Dammit: The show happened to be made about five years after everyone stopped using chalk for things like school boards, restaurants, and the many uses that seem to pop up in the show.
Due to hipster baristas, shop owners and street artists, Chalk seems to be making a comeback.