"The traditional purpose of Lent is the penitential preparation of the believer—through prayer, penance, repentance, almsgiving, and self-denial." A lot of focus has been placed on "giving up something for Lent," but neglecting the true meaning behind, which is to prepare ourselves for the death and resurrection of Christ. The purpose of giving up certain thing(s) in our lives for Lent is none other than reminding ourselves our utter reliance on God and God alone. Self-denial is a way of saying "I'm not the center of the universe," and sacrifice is an act that proclaims "I believe in God who is greater." It takes faith in God for the Israelite in the Old Testament to sacrifice their spotless and perfect lamb without blemish. It takes great faith in God for Abraham to put his son Issac on the alter (God delivered a ram to take Issac's place at the end). And finally, God made the ultimate sacrifice of giving His only Son for us. Observing Lent through self-denial is to remember what has been done for us.
The Lenten period is also an opportunity for us to remember how much we have been given and in contrast, how little others have. After all, none of the things we have belong to us (Psalm 24). We are but stewards of God's blessings and blessings are meant to be share. This is where initiatives like 40 Days of Water and 40 Days of Solidarity with the Poor come in. Giving up luxury items like coffee and/or adopting a simpler diet similar to those of developing countries are practical ways to reminding us that (a) God is our Provider; and (b) We are to take care of the poor. It's not too late to join these initiatives and donate the money to a charity which you'd have spent on drinks/food.
I hope at the end of the 40 days, we'll have a renewed and deepened sense of who He is, who we are, and what we are here to do.