Here are a couple of fairly recent small D&D variants you should check out.
Albert Rakowski's 8-page Bandits & Basilisks is a challenge offered to tinkering DMs everywhere. This text double dog dares you to drop all the stock D&D spells, magic items and monsters (except for the titular entities, the book's sample critters). B&B provides just about the barest framework possible for D&D. Don't skip the intriguing Arcane Lore rules or the smartly streamlined Treasure Chart.
At a more substantial 58 pages, Christopher Cale's Backswords & Bucklers provides a lot of interesting material for Elizabethan D&D with just a hint of Cthulhoid menace. If you like the idea of Blackadder II and Kit Marlowe getting drunk and fighting cultists and Spaniards in the London sprawl then check this baby out. Don't skip over the way each class earns XP in a different way. I'm seriously considering making use of the B&B rules for running out of hit points (called Downright Blows in the text). A list of further expansions to these rules is promised at the end and I sincerely hope we see them soon.