Psalm 16:11. The Episcopal psalter renders this as: "in your right hand are pleasures for evermore."
Luke 18:5. The NIV renders it as: "because this widow keeps bothering me, I will see that she gets justice, so that she won't eventually wear me out with her coming."
I suppose I have a dirty mind, but it's really, really distracting, at least to me. I stop thinking about the text and start thinking about the double entendre instead.
Edit: After I posted this, I thought of a case where I've seen translators deliberately duck such a misreading: Luke 11:7. The Greek has the man saying his children are *with him* in bed. This is open to misinterpretation in our cultural context, so different from the original context where a household might only own one bed. As you can see in http://bible.cc/luke/11-7.htm there are translations which work around this by saying "My children and I are in bed"; I'd be surprised if this wasn't a conscious choice to depart slightly from the Greek.