I have google adsense on my site, but the only thing is that that is the only advertisments I have on my site....
What other sites have something like Google Adsense?

like see below... that advertisment...
Where can I find something like that?

This ad is from http://chitika.com/mm_overview.php

Note that most ad companies (including Google) does not accept other ad company to be on the same page, so be sure to put only 1 ad company on your website.

Actually, I think Google only doesn't want you to have competing contextual ads... though I could be wrong, I haven't used Google Adsense in ages.

I think you could go with Google or Chitika and then something like Fastclick/Value Click or Tribal Fusion (though you probably don't qualify for those, try Burst! Media)

Those other companies I listed are not contextual advertisers, they use banner ads which are CPM/CPC.