It's fun to play video games, but what's even more fun is doing it for a good cause. Two times a year, expert gamers gather to showcase their skills by speedrunning through video games as fast as possible with the goal of raising money for various charities, such as the Prevent Cancer Foundation and Doctors Without Borders. This year's winter marathon - which started Jan. 3 and runs into the late night/early morning of Sunday, Jan. 10 - broke the $500,000 mark shortly before midnight last night. The event, managed by Speed Demos Archive and Speedruns Live, was first done in 2010.

Volunteer speedrunners play video games at incredible speeds for entertainment, while certain events inspire viewers to donate to the cause, according to the marathon's official website. Games are constantly streamed nonstop from beginning to end on Twitch. The games are played in single player, multiplayer co-op or competitive formats. Some runs last less than 10 minutes, while others last for more than an hour, but no matter the length of time, the speed and skill required to perform such feats is nothing short of impressive.

During the events, there are often donation-fueled challenges. Some donation incentives include bidding to name favorite game characters and donation competitions (bid wars). All donations go entirely to the charity the marathon supports.

Games featured in the marathon vary from classics - such as "Super Star Wars," "The Lion King" or "The Legend of Zelda" - to more current games like "Splatoon," "Devil May Cry 4: Special Edition" and "Resident Evil HD Remaster." A full list of game runs, time frames, challenges and other information are available via the event schedule. Check it out to see if they'll be streaming a run in one of your favorite games, past or present!

Miss a run in a game you love? You can watch previous Games Done Quick videos on the official YouTube page, as well as on Archive.

Take a look at the FAQs for more information on attending the events, submitting game videos, donations, etc.

As of 1:55 a.m., exactly 48 hours before the scheduled finale, the donations reached $534,583.72.

To donate and help support the Prevent Cancer Foundation's mission to stop cancer before it starts, click HERE. You can also track the donations and see how high they go HERE.

Will this winter's donations break a million dollars before the finale? It has in previous years, but only time will tell this year.