If you've delved into the world of Xbox Live Indie Games, the name Radiangames should sound familiar. Later this month, the studio is bringing four titles over to PC and Mac in a single package dubbed the Quadtastic Launch Collection.
Pre-order by January 24, when the bundle goes live, and you'll get Inferno+, Ballistic, Fireball, and Slydris -- all free of DRM. Other bundles are being offered by Radiangames as well, should you want access to extra content right now.
Playing up the charity angle, the more collections sold, the higher percentage of sales will go to a good cause (Child's Play and St. Jude's Children's Research Hospital). Do consider giving this one a perusal.