option 1 - Firebug lite
You visit any page and click the "Firebug lite" bookmarklet...
... then you hack away in the shiny console!
option 2 - built-in MS script editor/debugger
Go to menu Tools / Internet Options... / Advanced tab. Under the "Browsing" category uncheck the box that says "Disable Script Debugging"
Go to any page and cause an error, by typing in the address bar some non-existing property or some non-existing object for example. Like
Non-surprisingly, you get an error, but now you have the option of debugging the error:
You're given a list of debuggers, in case you've installed more debuggers from MS. Select your debugger or just hit Yes:
Just say OK here...
Finally - a console! We're in! The console is the so-called "Immediate" window, which is not displayed by default. To see it go to menu Debug / Windows / Immediate. Then just start fiddling with the page. Type anything and hit enter to see it evaluated. You also list the properties of an object by typing its name, like
document.images or just
Once you've had your fun, stop debugging:
Enjoy the results of your hard work, a.k.a. replacing some logo with a shot of your favorite book