The Pope says secular activities on Sundays are a sin.

Perhaps believing that church attendance and Christian reverence are at an all-time low because of more worldly diversions on Sundays (like, for example, watching “The Passion”, I suppose), the pontiff told a group of Australian bishops that they should tell their flock not to watch movies or sporting events on the sabbath.
Next, he'll be saying you can't lust after your wife, I suppose…whoops.