Dungeonslayers is free and seemingly very quick RPG to pick up, seeming relatively rules light. It sports some pretty cool artwork and an old school feel to it, and character creation is dead simple. There are many supplements you can also download for free from their downloads page including a book of monsters and a good selection of adventures that are ready to go. If you’re looking for a quick RPG with an old school feel, definitely check this one out.
Dungeon Crawl Classics
If you’re not already swimming in retro-esque fantasy RPGs and the above mentioned Dungeonslayers seems a little too simple for you then perhaps you should check out Goodman Games’ Dungeon Crawl Classics. The rules are in an open beta right now so you can download the whole rulebook filled with 160 pages of marvelous line drawing artwork and a solid RPG architecture. DCC contains lots of old school elements to the table like crit/fumble charts, hand rolling PC’s with various random tables to roll on and classes like Elf, Dwarf and Halfling. Yes classes, not races.
The rules contain some pretty cool mechanics such as spell duels – wherein wizards battle one another spell for spell, only one emerging from the chaos and the other a pile of dust. Another noteworthy element of DCC is that player characters must graduate from Henchman University before attaining any sort of status – starting out at level 0 with -100xp you roll up a stable of characters (takes about 2 minutes) and put them through the grinder, only the strong survive!
DCC is shaping up to be a well structured RPG based on games of yore, but with the flare and refinement of a modern RPG and is definitely worth a look!