[Shameless Plug]The blankets that are being knit for the Oddball Pet Snuggle Blanket project
in the Charity Knitting
forum are all two strands of two different color yarns held together. There are lots of finished and in progress photos in the thread if you would like to see some examples.
In these projects, the blankets are each made with five different color combinations, each made up of two different colored yarns.
Here's are a few that were recently completed and donated to local pet shelters by the last knitter of each blanket: