gistfile1.cs

void Main()
{
	var bob_banana = new person(){name = "bob banana", age = 5,friends = new List<string>(){"bobo", "bilbo", "brandon"}	};
	var tim_truffle = new person(){name = "tim truffle", age = 300,	friends = new List<string>(){"tom", "trudy", "trouble"} };
	var clyde_carrot = new person(){name = "clyde carrot", age = 30, friends = new List<string>(){"clog", "clod", "clop"} };
	
	var people = new List<person>(){bob_banana, tim_truffle, clyde_carrot};
		
	var info = people
		.Where (p => p.age > 20)
		.SelectMany(p => p.friends)
		.Distinct()
		.GroupBy (f => f.Length)
		.Select (g => 
			string.Format("There are {0} names with {1} letters"
				, g.Count()
				, g.Key
			)
		);
		
	info.Dump("Info");
	
	var quarryInfo = 
		from p in people
		where p.age > 20
		from f in p.friends.Distinct()
		group f by f.Length into g
		select string.Format("There are {0} names with {1} letters"	, g.Count(), g.Key);
	
	quarryInfo.Dump("Quarry info");
}

class person{
	public string name{get;set;}
	public int age{get;set;}
	public List<string> friends{get;set;}
}