Are they asleep or just challenging each other?

Have you ever noticed that the cats seem to sleep their entire day and most of their nights away?  They curl up anywhere and just fall asleep at the drop of a dime--just look at them, sleeping away, or are they challenging each other to see who can sleep the longest?  Hmm, I think they are working too hard at that challenge, just look, they have been asleep so long the spiders have moved in.....