Indiegames has put together a convenient wrap up of their top 20 free arcade games of 2007. There's something for everyone, and games running the gamut from simple to complex, with graphics to match. Garden Gnome Carnage not sounding like your cup of tea? Maybe Cottage of Doom or Winter's Heart will be up your alley. Most entries give a quick overview, screen shots, and a video of gameplay.
Best Freeware Arcade Games 2007 [Indiegames]