ElasticLINQ is a free C# library for searching Elasticsearch using LINQ syntax in .NET, e.g.

var db = new ElasticContext(new ElasticConnection(new Uri("http://myserver:9200")));
var p = db.Query<People>().Where(p => p.Tags.Contains("tech") && p.State == "WA");

ElasticLINQ supports .NET 4.5 & PCL with Elasticsearch 0.9.0 or greater.

Binary releases are available via NuGet. For information on getting started, see the Wiki.