Last year, I had a couple twin fork-horn bucks by my stand. They were banging their heads together and making some rubs for a while. After about half an hour, they got tired of that and laid down foranother half hour or so, about 15 yards from my stand. They both had their eyes closed for various lengths of time, probably not longer than 5 minutes at a time. Definitely asleep.
Then they got up, and walked away.
Short of shooting a deer, by far the coolest hunt I have ever been on as far as seeing things I've never seen before go.