Cloud gaming service OnLive said that the company will throw open its PlayPack vault in support of the Extra Life charity for 24 hours beginning Thursday, allowing gamers to play more than 250 games on the service for free.

Although the effort clearly promotes OnLive’s own services, the company is also raising money for Extra Life, a gaming marathon that helps raise money for the Children’s Miracle Network of 170 hospitals across America. The PlayPack is free, but those that raise money for Extra Life will also receive prizes that scale up according to the amount of money donated or raised.

Basically, OnLive sells itself as a way to play graphically intensive games without paying hundreds of dollars for the latest hardware. OnLive offers two main subscriptions. CloudPlay, for $7.95 per month, allows gamers who buy a supported game via Valve Software’s Steam service, to play the game using OnLive’s network of dedicated game servers. A second service, PlayPack, lets gamers play an archive of more than 250 older games that include Saints’ Row: The Third and the first two games in the Batman Arkham series, for $9.95 per month. OnLive also quietly bundled the two into an OnLive Service Bundle for $12.95 per month about two weeks ago.

Why this matters: OnLive’s service has always been very good, although the relaunch earlier this year adds the new pricing plans. Even a small donation to the Extra Life campaign, however, will unlock a month’s worth of free games. Either way, gamers have a chance to sample the OnLive PlayPack for at least 24 hours for free—and for a month just by paying a bit more. And that’s a win-win for both OnLive as well as Extra Life.

Gamers can sign up for an account Thursday at the OnLive website, where the OnLive PlayPack offer will be live. They can also visit the Extra Life website and donate additional money.

The “prizes” work as follows, according to OnLive:

Raise $5: One free month of the OnLive Service Bundle

Raise $25: First 1000 gamers get a free download of MX vs ATV Reflex from Nordic Games

Raise $50: A second free month of the OnLive Service Bundle

Raise $100: One free game code (up to $19.99)

Raise $200: A second free game code (up to $49.99)

Raise $300: Receive a third month of the OnLive Service Bundle + 1 free game code (up to $19.99)

Raise $500: Receive a fourth month of the OnLive Service Bundle + 1 free game code (up to $49.99) Additionally, the top 5 OnLive Team participants with the most donations by 6 a.m. PST on October 26, 2014, will receive their choice of a Mad Catz M.O.J.O. Micro-console + C.T.R.L.R. or a Wikipad 7-inch Gaming Tablet, the company said.

If you do participate, let us know in the comments!