This is a good one, but for different reasons than the ones you may believe. I'll explain those after I translate.

Your mother is a lovely woman.

Tu madre es una mujer muy linda

No mames güey, tu mamá es bien pinche fregona

Shit Dude, your mom is fucking cool

As I said, the translation back to english isn't that good.

Now, for the funny part. This may sound offensive, but tyou can say something that pretty much means the same, but will be particularly offensive to any Mexican, specially guys.

Tu mamacita está bien buena That single comment ends up being sexual, offensive and just plain vile.