It’s the summer, which means barbecues, swimming, and playing games really quickly to raise money for international charities. OK, maybe that last thing is fairly new as far as summer traditions go, but it’s definitely catching on.

The speedrunning community, which loves racing through games as fast as possible is getting together in Denver starting Sunday as part of a mass philanthropic effort. The event, called Summer Games Done Quick, will bring together some of the most talented and dedicated speedrunners in the world to play games in a marathon. The speedrunners will encourage fans around the world to donate to Doctors Without Borders, a humanitarian group that provides emergency medical care to people affected by armed conflicts around the world. You can tune into the event as it happens live on the gameplay video-streaming site Twitch. Summer Games Done Quick will run from June 22 to June 29.

Doctors Without Borders is in dozens of nations around the world, but it is best known for its efforts in war-torn countries. It currently has programs running inside of Syria and Iraq as those nations deal with civil war and sectarian violence. The money that gamers donate to watch someone play through Final Fantasy in just a few hours will actually go toward doing some good in places like that.

This is the 10th marathon for Speed Demos Archive and SpeedRunsLive, the two groups that cooperate to put on these events. They started in 2010, and each Games Done Quick event has grown larger than its predecessors. Summer Games Done Quick 2013 had speedrunners play through 90 games over six days, and viewers contributed over $250,000 to Doctors Without Borders. In the winter, the two groups held their Awesome Games Done Quick 2014 event, which saw 139 games played over seven days. Fans donated over $1 million to the Prevent Cancer Foundation during the course of that livestreaming event.

For Summer Games Done Quick 2014, Speed Demos Archive and SpeedRunsLive are planning to run through 156 games over seven days. The schedule is up on the site. The event will kick off with Super Mario 3D World for Wii U, and other highlights include The Legend of Zelda: A Link Between Worlds for 3DS, Aladdin for Genesis, and Tony Hawk’s Pro Skater for PlayStation.

If you haven’t seen a Games Done Quick event before, check out this awesome video from the last marathon that has four of the best Super Metroid players in the world racing one another:

Or this blind Super Punch-Out!! speedrun: