I usually do something good rather than give something up. This year I am trying to fast every friday . Not just no red meat but no food at all for 24 hours. I got the idea from this link:
http://www.30hourfamine.org/Display.asp?Page=Home
I am contributing the money that I would spend on food on those days to a local woman who gives formula and baby food to the children of abused women.
The way I figure it, no good can come out of my giving up pepsi, but some good will hopefully come from this.