Hostblock isn't a plugin already, it doesn't even run in the background and is only called to edit the block list. But if you find even that being too much (or just don't want to use additional apps), Internet Explorer 9 is
the browser to go.
Internet Explorer 9 introduced
Tracking Protection Lists
. These things are meant to block tracking, but blocking ads is not any different. Basically, you just have to go to a page which provides a list and subscribe to it. I, for my part, recommend
By the way, Hostblock can export Tracking Protection Lists too. After doing that, you'll have to upload this list on some web server and make some page calling