My now almost-grown-up kids have been playing Guess Who? since they were kindergartners. They began by asking  questions in a straight-forward, age appropriate way ("Does your person have a mouse-stash?"), and then learned to refine their queries in order to narrow down their choices ("Does your person have facial hair?"). Well into their teens, they still enjoyed our now-faded and probably incomplete set . By now their questions were highly evolved - or devolved, depending on your point of view: "Does your person look like he just got dumped by his girlfriend?" "If your person stuck his head out of a moving car, would he beat himself to death with his lips?" Some of their other favorites fell into the frat-boy humor category, but provided many hours of laughs - and years of "in" jokes they assumed I didn’t understand. 

Some other family favorites:

• Chutes and Ladders: Relatively fast and easy for neophyte counters
• Sorry : Good training for sore losers.  Excellent for developing a sarcastic tone ("SOOOORRRY"said with a slight sneer.)
• Trouble: The pop-o-matic never gets old)
• Pictionary: Lots of fun for a crowd of all ages
• Balderdash: My personal favorite, especially with teens.

A new favorite: Bananagrams, a tile-based word game where you build your own crosswords. Even novice spellers will enjoy this hands-on game. Have them play on your team when they’re starting out.