Sure:
HeroQuest: take D&D hero miniatures, put them on the map included in the 3.0 DMG, and add the occasional orc or door miniature, and you have a great gateway drug for RPGs - or a game called HeroQuest. It was well done, if I recall.
or,
Risk: whether you want to be George W. or Kim Jong Il, Risk provides the framework and the gameboard. I think Risk actually mentions in the rules that it's house rule-friendly.
As for RPGs, some that I've played,

: who sets out to write their non-favorite game? Some broad features that I like are short rules, fast character and monster generation, and a very simple dice rolling/result system. Maybe someday will it have more special gear, monsters, and artwork.

: the mercifully streamlined version of 3.5. Odds are that the DMG will re-introduce the headaches of 3e, but the PH is really a great improvement.

: the mercifully remastered version of 3e. Fun game, cool abilities, fun combat tactics. And with top-notch splat books, of which I own many.
...and some I haven't,

: simple rules, fast play, genre flexibility - is this not a GM's dream come true?

: grow your character's stats from his life experiences? Heck yeah! And if he gets caught in a wormhole and sent to the future, well, you can keep using the same rules.
Zweihaender: the dark ages were not a very safe time for living. Anarchy, baby. This game looks like it will catch that flavor well.
Far Away Land: simple, quirky rules for an eye-catching fantasy game. And I'd really love to play through the setting-generation module.
Final Fantasy d6: this game looks to effectively catch both the mechanics and the theme of Final Fantasy combat and roleplaying. But it's a little bulky, which might help to explain why I've never found a game to hop into. (Why is there no FF icon? The name is almost as old as D&D!)
Well, that's 10. Happy gaming!