Sure, tomorrow is Abraham Lincoln’s 200th birthday – and there are 200 candles on Charles Darwin’s cake as well – but in the CauseWired world, there’s a bigger pin on the calendar: yes, it’s Twestival.

The premise is incredibly simple: more than 175 cities around the world will be hosting Twestivals which bring together Twitter communities for an evening of fun and to raise money and awareness for charity: water. Every event is different – but they all raise money for clean drinking water in the developing world.

In Montclair, NJ, for instance, organizers plan a night out at a local restaurant with a singer-songwriter and French Macarons. In Amsterdam, there’s a social media workshop and live music. Liverpool is hosting a massive charity auction with some great art-related items. Jerusalem has wine tasting and a giant bubble-making artist. Bogota has a giant disco on tap.

Admission to in-person events is generally less than $10 – and charity: water is also raising money through online donations and T-shirt sales. Of course, all the organizing (well, most of it) has been done in 140 characters or less. The charity: water pitch is a simple one:

Right now 1.1 billion people on the planet don’t have access to safe, clean drinking water. That’s one in six of us.

Unsafe water and lack of basic sanitation cause 80% of all sickness and disease, and kill more people every year than all forms of violence, including war.

Many communities in developing nations often have a plentiful supply of clean drinking water just below the ground, but no way to get to it.

This is where charity: water and their partner organizations come in. Drilling a well can cost from $4,000 – $12,000 USD and many living on less than $1 a day cannot afford one in their community, even if the money is combined.

Scott Harrison, a former nightclub promoter from New York, founded charity: water in 2006 after a trip to Africa, and brought his talent for the world of promotion, organizing, media and celebrities to the clean water movement. He estimates that Twestival will raise more than $1 million in one day. Should be interesting to follow the #twestival tomorrow.

Twestival, Twitter, Water Poverty, Twitter