Depends on what you want to spend....
For a large enough budget:
Charity + Viral Marketing = Profit (well, maybe... or charitable profit) + Better Life for Someone....
Set yourself up with a social experiment. Find a truly deserving homeless family. Seriously. $5k can change an entire family's lives, if you find the right family.
• Rent on a 2 bedroom apartment for 3 months (assuming you don't live in, say, Cali): $2,000
• Inexpensive vehicle that will get them to work, kids to school, etc: $1,500
• Insurance on said vehicle for 3 months (or more): $200
• Basic work and school clothing for a family of 4: $600
• Basic (but clean and usable) second hand furniture and necessary household goods: $700
Bonus points if you do all of the above for a family of victims of domestic violence. The key is in asking around to people (not just their friends) to find out who is worthy of your assistance. Many of these families will qualify for medical support and food stamps, and for the right family, the above will be everything they need to get back on their feet and change their lives. More work? Of course. But there's a helluva lot more reward when you're personally invested in the family. Don't feel bad about asking them to sign a contract stating they'll pay back x amount over x years, in $xx per month payments.... Just don't *count* on getting that money back, and you'll be pleasantly surprised if you do.
Now to profit (or charitably profit.. or both.. adsense, perhaps?) , while building up funds to help the next family: blog (or pay someone else to) all of the above. Generate traffic, stick a donate button on there, and spread it around FB. There's a pretty good chance that by the time the first $5k is spent on the family, there'll be another $5k waiting for the next family. With any luck, in 3 months' time the family chosen (especially with the internet exposure) will have employment, and a better life.