Added support for DynamicLinq in place of Lambda syntax. The short version is you can't use a Lambda with a DynamicNode

e.g. @Model.Children.Where(node=>node.shouldBeVisible)
To solve this, I used the DynamicQueryable class from the Linq samples which has a parser that can take a string then modified the internals a bit so
that if your object is a DynamicObject, an additional expression tree is generated which calls the TryGetMember on it
The end result is that you can now do this [I have Random(this DynamicNodeList nodes, int max) in my bin folder]
@Model.Children.Where("shouldBeVisible").Random(2) => two nodes, randomly picked, from the ones that should be visible
*Only* Where is implemented here currently, I'll add support by OrderBy and ThenBy after I've tested some more complex scenarios.
I need to fix a small issue with my DynamicLoading of extensions - under some scenarios the class doesn't get found and i'm not sure why.

umbraco.MacroEngines.Juno/DynamicDictionary.cs

@@ -15,7 +15,14 @@ namespace umbraco.MacroEngines
         }
         public override bool TrySetMember(SetMemberBinder binder, object value)
         {
-            _dictionary[binder.Name] = value;
+            if (_dictionary.ContainsKey(binder.Name))
+            {
+                _dictionary[binder.Name.ToLower()] = value;
+            }
+            else
+            {
+                _dictionary.Add(binder.Name.ToLower(), value);
+            }
             return true;
         }
         public override bool TryGetMember(GetMemberBinder binder, out object result)

umbraco.MacroEngines.Juno/DynamicNode.cs

@@ -370,7 +370,11 @@ namespace umbraco.MacroEngines
         {
             get { if (n == null) return null; return n.Name; }
         }
-
+        public bool Visible
+        {
+            get;
+            set;
+        }
         public string Url
         {
             get { if (n == null) return null; return n.Url; }

umbraco.MacroEngines.Juno/DynamicNodeList.cs

@@ -8,7 +8,8 @@ using System.Collections;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Web.Compilation;
-
+using System.Linq.Expressions;
+using System.Linq.Dynamic;
 namespace umbraco.MacroEngines
 {
     public class DynamicNodeList : DynamicObject, IEnumerable
@@ -31,6 +32,13 @@ namespace umbraco.MacroEngines
         public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
         {
             var name = binder.Name;
+            if (name == "Where")
+            {
+                string predicate = args.First().ToString();
+                var values = args.Skip(1).ToArray();
+                result = new DynamicNodeList(this.Where<DynamicNode>(predicate, values).ToList());
+                return true;
+            }
 
             try
             {
@@ -209,5 +217,10 @@ namespace umbraco.MacroEngines
         {
             return Items.GetEnumerator();
         }
+
+        public IQueryable<T> Where<T>(string predicate, params object[] values)
+        {
+            return ((IQueryable<T>)Items.AsQueryable()).Where(predicate, values);
+        }
     }
 }

umbraco.MacroEngines.Juno/umbraco.MacroEngines.csproj

@@ -63,9 +63,11 @@
   <ItemGroup>
     <Compile Include="DLRScriptingEngine.cs" />
     <Compile Include="DynamicDictionary.cs" />
+    <Compile Include="DynamicQueryableBinders.cs" />
     <Compile Include="DynamicMedia.cs" />
     <Compile Include="DynamicNode.cs" />
     <Compile Include="DynamicNodeList.cs" />
+    <Compile Include="DynamicQueryable.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="RazorEngine.cs" />
     <Compile Include="Scripting\MacroScript.cs" />