Ikariam Wikibar
There exists a popular browser-based strategy game called Ikariam created by the German team Gameforge. There also exists an in-depth Wiki about the game called WikIkariam.
Ikariam Wikibar is a Greasemonkey script that creates a sidebar on the left edge of the game window. When you mouse over the sidebar, it expands to reveal WikIkariam. (Note: The wiki will not load until you mouseover the bar. This way, you won't have to re-load the wiki every time you browse to another page in the game.) You can browse the Wiki for information without ever leaving Ikariam's website!
Ikariam Notebar
Adds a small tab to the left side of the game window. When you mouseover it, it will expand to show you the note taking window. Click into it and begin typing. The script saves what you type as you type it so you don't have to worry about clicking any save buttons. Click the tab again and it hides it!
Ikariam Quickbar
Adds a tab to the left side of the game window that holds "Quickmarks" for you. When you find a page that you'd like to save, expand the tab and click "Quickmark current page" to name and save it. Later, you can open the tab and click one of your quick quickmarks to visit it! Mouse over the tab to expand it and click again (or mouseout) to close it.
Ikariam Fightbar
This script adds a tab to the left of the game screen that will slide
out when moused over to reveal the Ikariam Fight Simulator.