There are two ways that we've been able to get mammals to live longer: genetic engineering, and calorie restriction. Neither of those things sounds like much fun, but scientists may have just stumbled onto a drug that can also extend your lifespan, by a decade or more.
The drug in question is called rapamycin, and it's derived from a soil bacteria found only on Easter Island, which seems appropriate somehow. When mice were fed the drug at 20 months of age (equivalent to about 60 years old for a human), it boosted their lifespan by between 8% and 13%. To be clear, the mice only started taking the drug when they were technically old already, and it still significantly extended their lives.
Nobody's really sure, at this point, exactly how rapamycin (an immunosuppressant) does what it does. The suspicion is that it may take advantage of the same biochemical pathways as calorie restriction, but what's important is that the mechanism that rapamycin uses to function is the same for mice, fruit flies, nematode worms, and yeast, suggesting that it's a common enough thing that it's probably good to go in us humans, too.
As with most drugs, rapamycin does have some side effects: as an immune suppressant, taking it increases your risk of things like fungal infections and pneumonia, which is why not starting to take it until later in life might be a good idea, although scientists are currently experimenting (in mice) with different dosages taken earlier in life. For humans, what could be most realistic is to use rapamycin to treat primarily age-related disorders (instead of aging in general), but this hasn't prevented some fairly optimistic assertions on the part of the researchers:
"Realistically," says Kaeberlein, "I think what most of us are hoping for, and are somewhat optimistic about, is the idea that you may be able to get an extra decade — possibly an extra two decades — of relatively good health."
Yeah, I'll take it.