Judging by the total contributions to the "Humble Indie Bundle" charity drive, gamers are a bit more willing to give to charity as long as they get a little something in return.

Contributions to the "Humble Indie Bundle" exploded over the past week, as contributions grew from about $40,000 on May 4 to around $700,000 Monday morning. The total number of contributions grew from about 5,300 to about 82,000, while the average contribution grew from $7.59 to $8.51.

The "Humble Indie Bundle" initiative, which ends this week, allows consumers to pay what they want for a six-game indie bundle, with the option of giving all proceeds to charity. The idea is spearheaded by indie developer Wolfire Games.

According to the Humble Indie Bundle website, just over half of the contributors bought the Windows version of the game, with the rest split nearly evenly between Linux and Mac users. Windows contributors averaged $7.33 per contribution, Mac users $9.79 and Linux users $13.98.

At the Humble Indie Bundle's website, buyers can choose any amount of money to pay for the pack. They can then choose to donate to Penny Arcade's Child's Play charity toy drive, the non-profit digital rights advocacy group Electronic Frontier Foundation or the game developers. Buyers can also decide how they want to split their contributions between the recipients.

The Humble Indie Bundle includes Independent Games Festival 2007 Seumas McNally Grand Prize winner Aquaria from Bit Blot, Cryptic Sea's 2005 IGF grand prize winner Gish, Wolfire Games' Lugaru HD, Frictional Games' Penumbra: Overture and 2D Boy's multiple IGF category award winner World of Goo. Amanita Design also recently added Samarost 2 to the bundle.

Combined, the DRM-free games are valued at around $80 if purchased separately.