I'm quite active on Facebook, where I've got several friends from English speaking countries. They often post things like that.
There are lots of places where you can buy T-shirts, mugs etc. like this, but probably only in the US or Britain, I don't know:
Like this, it's a German address:
Just google: funny grammar t-shirts, and you'll find loads of posts.
Are you on Facebook? Then you could 'like' the grammarly-page. They often have hilarious posts!
Your husband might like these: