Garnfellow
Explorer
Based on what I can gather about your tastes (somewhat old school) and the casual nature of the game you're describing, I think Wilderlands might be a good fit. It's almost the perfect setting for a pickup game -- very broad and very shallow, easy to just plunk down in front of players and run; no detailed histories or deep cultural immersion to worry about, just lots and lots of places to go explore, kill things, and take their stuff. My guys were fascinated just by the maps, which have plenty of evocative names.
The only caveat about Wilderlands is the old school nature that is so appealing to some can be downright appalling to others. The setting contains several science fantasy elements, which can drive many people bonkers. It also has many punning and jokey names, which can also be kryptonite to some folks. Both of these aspects can be easily ignored, but if they don't give you pause then Wilderlands might be just the thing for you.
The only caveat about Wilderlands is the old school nature that is so appealing to some can be downright appalling to others. The setting contains several science fantasy elements, which can drive many people bonkers. It also has many punning and jokey names, which can also be kryptonite to some folks. Both of these aspects can be easily ignored, but if they don't give you pause then Wilderlands might be just the thing for you.