Juicyads - argh
Undoubtly the adult source with the ugliest and most unusable interface. However also a source of many hidden traffic gems (mostly for direct buys)
Since their interface looks like its been patched up from 5 different design concepts and then assembled together by someone with an attention disorder syndrome,
its possible to take a peek at the live filler campaigns
1) You need to have some page reported as a publisher (so you need to have 1 publisher page active)
2) Under manage my ads, you have in Publisher ads section a link Block campaigns
3) Click on advanced campaign blocking
Voila.. yout get a list of "presumably" live ron filler banners and in some cases also the lps.