The contents of the Voyager Golden Record. Despite our wars, our pettiness, and our greed, we look to be more than what we are, and we look for others living out there so that we can deliver to them a message from all of humanity of hope, friendship, and goodwill.
This video and this video, featuring a baby boy and a 29 year old woman respectively, both born deaf, hearing for the first time. Medical science gave them their hearing, and in this editor's experience, no one who has seen these videos has failed to choke up in the good way.
Jonas Salk's greatest achievement was developing the vaccine for Polio, a disease so widespread and crippling in parts of the world that China had 80 million people vaccinated in 1993, and is still a big problem in third world countries. A man who could have become one of the richest scientists in the history of humanity said these words when regarding a patent "Could you patent the sun?". Because of this work, Polio went from hundreds of thousands of cases per year to about a thousand... Tens of millions of children, able to walk, because a man would rather do the right thing rather than get rich...
This is so heartwarming, that Jonas Salk being the original "Good Guy Greg" (a reddit macro series) is practically a meme.
In a poor Malawian village racked by cholera, famine, and superstition, a young boy gets kicked out of school because he can't afford the tuition. The boy, however, loves science and learning, and is determined to keep learning. So... he fishes out scraps of books from the local dumpster. He finds a book on basic electricity, and sees a picture of a windmill that generates electricity. His imagination sparked, he spends the next year and a half digging through trash cans and other stuff people have either thrown away or are about to throw away; to find the parts necessary to make his windmill. People call him mad, but his parents tell him to keep working at it. One day, the boy calls his village together (Please keep in mind, the highest technology anybody in the village owns is an AA battery and maybe a walkman) and holds up a single light bulb attached to a windmill that looks like a reject from a Dr. Seuss book. The villagers laugh at him... UNTIL... the light bulb flickers. As the wind picks up, the rickety windmill spins, and suddenly the light bulb shines, like a single candle in the night. The stunned villagers cheer the boy wildly. Soon word of the boy's genius spreads (remember, he basically just brought his village out of the third world, a feat that whole governments sometimes fail to achieve). The new found hi-tech is used to aid in getting clean water to use for the crops, thus alleviating the devastating famine. And the kicker... the boy gets a scholarship to COLLEGE in South Africa and is called a hero by Al Gore himself. Nobody has the audacity to make up a story like this. Just Google William Kamkwamba. Better yet, here's a entry on him from The Other Wiki.
One manufacturer of these robots has gone on to say that one of the oddest, yet hardest things he has ever seen was when he saw big, tough soldiers come to him on the verge of tears, giving him a thoroughly bomb-blast destroyed robot and begging him to fix it.