Okay, vegetarianism is easy. I suppose if I really wanted to push myself, I'd try going vegan.
Truth be told, I tend to give up meat for Lent anyway, so this hasn't really been too difficult. There have been some times when I'd really like to eat a piece of bacon or just grab a burger, but not too many.
Now I have to decide what I'm going to do for the next month. I'm thinking of trying something really difficult like working out or writing every day. That would take some real effort and discipline. I'll think about it. Of course, I'm open to suggestions.