I'm not Catholic, but do observe Lent; I came up with this idea one year when I was already eating such a strict diet that there was nothing left to give up!
I covered my hair. Now, I am basically a pretty down-to-Earth, low-maintenance type of woman, but I am absolutely anal about my hair. How I wash it, what to wash it with, conditioners, leave-in conditioners, hairstyles, accessories...you name it. So I decided I would cover my head, at least in public, during Lent--"giving up" my pride. It turned out to be one of the most meaningful things I've ever done, and it eventually led to me covering my hair full-time.
Another nice idea--a church that I belonged to at the time gave everyone Lenten calendars and a piggy bank (actually, just a mason jar with a slot cut in the lid). The calendar had a different blessing/privilege every day that you were to pay attention to, and a small amount of money to 'donate' in gratitude.
For example, one day might be "5 cents for every pair of shoes you own,"
another day might be "25 cents if you took a hot shower today,"
another day "$1 if you have electricity in your house,"
or--gulp!!--1 cent for every pound you weigh."
The amount of money to be donated any given day was always small, and the blessings/privileges were things that almost all of us would possess (food, shelter, the ability to read, owning a car, etc.). At the end of the Lenten season, piggy banks were collected and the money given to a worthy cause. Maybe you could do something like that? It really made me aware of how blessed I am.