I have a pair of womens jeans that I wear regularly. Even my wife doesn't realise that they are womens. I cut out the size label, so she's not likely to find out, either. The zip is sewn in "left handed" which catches me out sometimes, but nobody else appears to have noticed.
Years ago, I used to wear fairly close fitting stretch jeans that were sold as "unisex", although the size label had womens sizing on them, so I guess they were really womens but were cut generously enough at the front to fit men without crushing the family jewels.
Having said that, men and women alike wear jeans and some womens jeans seem to be cut the same as mens anyway.
I have worn womens jumpers before though, but again, you could consider them to have been a fairly unisex design.