I've taken to not giving homeless people any money anymore, not because of their obvious substance abuse issues, but because times are rough like mustard.
Instead I usually amaze them with some street magic, they usually act as if its not something they were expecting! Which is a joyful feeling. Here's a simple little trick to show the working classes: All you need is one house fly, and a working freezer. Shortly before you go out to find a homeless person, catch a fly and pop it into a freezer for 1 minute or so, basically enough to place it into cryo-sleep.
Remove the fly from the freezer, and pop it into a matchbox.......
Find your homeless person and instead of giving them money, quickly off load the sleeping fly near them. You could then give them a pep talk about the resurrection of Jesus, drawing similarities to their own lifestyle, and make a comparison with dead flies.
You then pick the sleeping fly up, breath gently on it (your warm breath will wake it up) and get ready for sponaneous applause from the crowd gathered around you! This was actually how I met my wife.