I couldn't find an easy way to generate ical or JSON feeds in ASP.NET. This is what I created to get that done.

Calendar.cs

/*
  Class: Calendar
  Created by: Mike Wills (http://mikewills.me)
*/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Text;

namespace SupervisorPayroll.Models
{
    #region Event
    public class Event
    {
        public string Title { set; get; }
        public string Description { set; get; }
        public string URL { set; get; }
        public string UID { set; get; }
        public DateTime DateTimeStamp { set; get; }
        public DateTime CreatedDateTime { set; get; }
        public DateTime Start { set; get; }
        public DateTime End { set; get; }
        public bool AllDay { set; get; }
    }
    #endregion

    public class Calendar
    {
        #region Model
        public string CalendarName { set; get; }
        public string Product { set; get; }
        public string TimeZone { set; get; }
        public List<Event> Events { private set; get; }
        #endregion

        /// <summary>
        /// Initializes a new instance of the <see cref="Calendar"/> class.
        /// </summary>
        public Calendar()
        {
            Events = new List<Event>();
        }

        /// <summary>
        /// Adds the event.
        /// </summary>
        /// <param name="eventItem">The event item.</param>
        public void AddEvent(Event eventItem)
        {
            Events.Add(eventItem);
        }

        /// <summary>
        /// Creates an Ical string.
        /// </summary>
        /// <returns></returns>
        public string ToICalString()
        {
            const string EOL = "\r\n";
            StringBuilder sb = new StringBuilder();

            sb.Append("BEGIN:VCALENDAR");
            sb.Append(EOL);
            sb.Append("VERSION:2.0");
            sb.Append(EOL);
            sb.Append("METHOD:PUBLISH");
            sb.Append(EOL);
            sb.Append("X-PUBLISHED-TTL:PT60M");
            sb.Append(EOL);
            sb.AppendFormat("PRODID:{0}", Product.Replace(",", "\\,"));
            sb.Append(EOL);
            sb.AppendFormat("X-WR-TIMEZONE:{0}", TimeZone);
            sb.Append(EOL);
            sb.AppendFormat("X-WR-CALNAME:{0}", CalendarName.Replace(",", "\\,"));
            sb.Append(EOL);

            foreach (Event eventItem in Events)
            {
                sb.Append("BEGIN:VEVENT");
                sb.Append(EOL);
                sb.AppendFormat("UID:{0}", eventItem.UID.Replace(",", "\\,"));
                sb.Append(EOL);
                sb.AppendFormat("DTSTAMP:{0}T{1}Z", eventItem.DateTimeStamp.ToString("yyyyMMdd"), eventItem.DateTimeStamp.ToString("HHmmss"));
                sb.Append(EOL);
                sb.AppendFormat("CREATED:{0}T{1}Z", eventItem.CreatedDateTime.ToString("yyyyMMdd"), eventItem.CreatedDateTime.ToString("HHmmss"));
                sb.Append(EOL);

                if (eventItem.AllDay)
                {
                    if (eventItem.End.Date != DateTime.MinValue.Date)
                    {
                        sb.AppendFormat("DTSTART:{0}T000000", eventItem.Start.ToString("yyyyMMdd"));
                        sb.Append(EOL);
                        sb.AppendFormat("DTEND:{0}T000000", eventItem.End.AddDays(1).ToString("yyyyMMdd"));
                        sb.Append(EOL);
                        sb.Append("X-MICROSOFT-CDO-ALLDAYEVENT:TRUE");
                        sb.Append(EOL);
                    }
                    else
                    {
                        sb.AppendFormat("DTSTART:{0}T000000", eventItem.Start.ToString("yyyyMMdd"));
                        sb.Append(EOL);
                        sb.Append("X-MICROSOFT-CDO-ALLDAYEVENT:TRUE");
                        sb.Append(EOL);
                    }
                }
                else
                {
                    sb.AppendFormat("DTSTART:{0}T{1}", eventItem.Start.ToString("yyyyMMdd"), eventItem.Start.ToString("HHmmss"));
                    sb.Append(EOL);
                    sb.AppendFormat("DTEND:{0}T{1}", eventItem.End.ToString("yyyyMMdd"), eventItem.End.ToString("HHmmss"));
                    sb.Append(EOL);
                }

                sb.AppendFormat("SUMMARY:{0}", eventItem.Title.Replace(",", "\\,"));
                sb.Append(EOL);
                sb.AppendFormat("DESCRIPTION:{0}", eventItem.Description.Replace(",", "\\,"));
                sb.Append(EOL);
                sb.AppendFormat("URL:{0}", eventItem.URL);
                sb.Append(EOL);
                sb.Append("END:VEVENT");
                sb.Append(EOL);
            }

            sb.Append("END:VCALENDAR");
            sb.Append(EOL);

            return sb.ToString();
        }

        /// <summary>
        /// Creates a calendar json string.
        /// </summary>
        /// <returns></returns>
        public string ToFullCalendarJsonString()
        {
            StringBuilder sb = new StringBuilder();

            sb.Append("[");

            int count = Events.Count;
            int i = 0;

            foreach (Event eventItem in Events)
            {
                sb.Append("{");
                sb.AppendFormat("\"title\":\"{0}\",", eventItem.Title);
                sb.AppendFormat("\"allDay\":\"{0}\",", eventItem.AllDay);

                if (eventItem.AllDay)
                {
                    sb.AppendFormat("\"start\":\"{0}T00:00:00\",", eventItem.Start.ToString("yyyy-MM-dd"));
                    sb.AppendFormat("\"end\":\"{0}T00:00:00\",", eventItem.End.ToString("yyyy-MM-dd"));
                }
                else
                {
                    sb.AppendFormat("\"start\":\"{0}T{1}\",", eventItem.Start.ToString("yyyy-MM-dd"), eventItem.Start.ToString("HH:mm:ss"));
                    sb.AppendFormat("\"end\":\"{0}T{1}\",", eventItem.End.ToString("yyyy-MM-dd"), eventItem.End.ToString("HH:mm:ss"));
                }
                sb.AppendFormat("\"url\":\"{0}\"", eventItem.URL);
                sb.Append("}");

                i++;

                if (i < count)
                {
                    sb.Append(",");
                }
            }

            sb.Append("]");

            return sb.ToString();
        }
    }
}