Government is not in the business of helping anyone. Honestly your money would be better spent on lottery tickets or really anything else (at least you are supporting real people with real jobs when you do this). If you are looking for a tax write off then find a charity or an organization that is actually concerned with a just cause.
What is your donation to Uncle Sam going to do? Support more wars, entitlements, and other worthless government endeavors ... no thanks. I won't even just pick on the U.S. as really no governemnt is worthy of a dime of voluntary support let alone billions of dollars.
Take the 5 or 10 dollars and put it towards a game or something you enjoy. You will be happy to do something nice for yourself, and you can rest comfortably knowing that you are not actively supporting wars and coercion.