First Sunday in Lent

While purusing Jimmy Akin's blog, I came upon his great Sundays in Lent Controversy, Parts I through V.

The issue: Does one keep to one's Lenten practice, even on Sunday, the Lord's Day, which is a day for celebration and not a good day for penitential acts?

"Giving something up for Lent" is purely optional, of course, so it's certainly not a sin to indulge on Sunday.

Personally, when I give something up, I give it up every day until Easter. I think that's the more traditional, easier-to-remember way of doing it, anyway.