While browsing through Firefox addons in my spare time, I just found this great Firefox addon that can very well kill your boredom and will surprise you with different visuals everytime you play it.
Destroy the Web can convert any webpage into a mini videogame, you can then blast the elements on that web page and earn points, within a limited time. Here are some of the screenshots of when I tried out that addon:
In short, this addon will fit your need, when you just need to blast out. The only disadvantage I can see in this addon is its size: 4 Mb should be pretty much for a Firefox addon. But then, it fits the size, and makes playing the game on every webpage a different experience.
This addon installs a little icon on the botton status bar of Firefox, clicking which you can start destroying any webpage you want. Also after the game you can submit your score, which you can then compare with other people via a database that is maintained on the developer’s website.
You can install this addon from here. (Firefox 3.5 and later compatible)