Launch Unity from Visual Studio

launch-unity.ahk

IfWinExist, ahk_class UnityContainerWndClass
{ 
    WinActivate 
    Send ^p ; sends Ctrl+P
}
else 
{ 
    MsgBox, 64, Unity is not open. Please open the project to run from Visual Studio. 
}

program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace UnityRunSwitcher
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            System.Diagnostics.Process.Start("launch-unity.ahk"); // new
        }
    }
}

Blog post: http://jay-wick.com/2014/04/start-playing-unity-project-from-visual_19.html
Known issues: won't open the same solution from Unity since SLN is different :(