Then you might want to check out Robin’s Hammocks, a site which sells all kinds of comfy fun things for ratlets.
The colours of this particular set aren’t to my taste, but there are tons of other options! :-)
Note: I haven’t ordered from this site, myself, but I did meet the lady who runs it a few years ago, and the quality of her hammocks looks pretty good from the photos.
Robin’s Hammocks: http://robinshammocks.weebly.com/index.html (please note that she lists a rescue site which no longer exists called Chelle’s Critter Haven)
Pet Smart: http://www.petsmart.com/
Want to know more about pet rats? Check this site out: http://www.ratfanclub.org/ (please note, some of their information is a little out of date)