It seems like the problem with it not working very time is Github. I get a 503 on this URL every other time that I load it: http://rawgithub.com/briangonzalez/jquery.adaptive-backgroun...
The author of this seems not to have paid attention to that, which is particularly silly since the page is hosted on GitHub pages, and the assets can (and should) be hosted there as well.
In any case, I've now moved the library to also be hosted on Github pages.