There are traditionally three basic Lenten practices which are supposed to be integrated together: prayer, fasting, and almsgiving. This last is often forgotten, but one of the most important reasons for Lenten fasts and abstinences is to let you focus on more important things like doing good to those who need it.
If you are looking for a possible charity to support, you might consider Christopher Adare's Asatayike project; Adare does work in developing sustainable agricultural practices in Malawian villages, through Children of the Nations.
If you are anywhere near Phoenix, AZ, you might consider donating to André House of Arizona; you are anywhere near LA you might consider the Jewish Vocational Service; and if you are anywhere near South Dakota, you might consider the Native American Heritage Association.
Both Catholic Charities USA and International Orthodox Christian Charities do a great deal of good work, and in the past I've found the latter, especially, to be pleasant to work with.