Have fun replacing all instances of one word with another on pages you visit.
This extension lets you change a word of your choosing with a different one on websites that you're viewing.
For instance, you can change "Bill Gates" to "Shrek" on his Wikipedia page! What fun!
Configure the search and replace words in the extension. Then click on the extension in your browser while on a page where you want to do the word changing, and voila!
Note that this is actually written by my 8 & 10 year old sons, who think this is the best way to learn how to program.