You should know, if you don't already, that I'm a big fan of graphically enabled, boiled down adventure game rules; also, that a good chunk of this blog is about my attempts to create such rules; also, that I'm not the greatest freehand artist, which I compensate by using an Isotype-style design aesthetic, so I stand perpetually in awe of works like Kata Kumbas with their gorgeous illustrated equipment shops and catalogues.
Another enviable work, just released by Doug Anderson of the Blue Boxer Rebellion blog, is the kid-friendly player pack (pdf) for his RPG Dungeonteller.
One page rules supplements, you say? Procedural rules for the whole game are a spacious, breezy one page. The rest is content, including great character illustrations, and equipment-shops with price tags. Many neat touches, including different font sizes to make your character's good skills really stand out. Advancement, resolution, basic equipment - everything for players is here, on an ample and very readable two-sided character sheet.
A more conventional presentation of the full Dungeonteller game can be found here (pdf), including a nice little tutorial scenario. Both downloads are free.