"Blockland is an online multiplayer building game.
It's like playing with legos on the internet." 1
1 http://www.blockland.us
That's a Chicago style citation not MLA.
MLA citations are a general format and you drop or add things depending on what's required and what's available. If there is no author you just skip the author section.
So for example, here is a general citation:
"<Page Title>" <Site Name>. <Publisher>, <Date Published>. Web. <Date Accessed>
So a citation from the front page of, say, something awful, would be:
"Death Panel" Something Awful. Mobutu Sese Seko, 29 Apr. 2010. Web. 2 May 2010.
We have the author and date published so it's pretty easy. Now suppose we want to cite the specifications of a mini-fridge on newegg. We don't have a publisher or date published. So we do this instead:
"Haier 1.7 cu. ft. Refrigerator/Freezer flush back" Newegg. n.p., n.d. Web. 2 May 2010.
n.p. stands for no publisher and n.d. stands for no date.
If you still have time, ask your teacher if this citation is okay because they might still want you to use the old format for some reason. I know teachers who were still assigning projects with the out of date guidelines because they were familiar with it. Otherwise just jump right in and do it this way.
In the old format you would just skip the author. So the above citation would be:
Haier 1.7 cu. ft. Refrigerator/Freezer flush back. <http://www.newegg.com/Product/Product.aspx?Item=N82E16896741148>. Accessed 2 May 2010.
or however it was supposed to be done, I can't remember.