DateTime extension methods

DateTimeExtensions.cs

public static bool Between(this DateTime dt, DateTime rangeBeg, DateTime rangeEnd)
{
    return dt.Ticks >= rangeBeg.Ticks && dt.Ticks <= rangeEnd.Ticks;
}

public static int CalculateAge(this DateTime dateTime)
{
    var age = DateTime.Now.Year - dateTime.Year;
    if (DateTime.Now < dateTime.AddYears(age))
        age--;
   return age;
}

public static string ToReadableTime(this DateTime value)
{
    var ts = new TimeSpan(DateTime.UtcNow.Ticks - value.Ticks);
    double delta = ts.TotalSeconds;
    if (delta < 60)
    {
        return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";
    }
    if (delta < 120)
    {
        return "a minute ago";
    }
    if (delta < 2700) // 45 * 60
    {
        return ts.Minutes + " minutes ago";
    }
    if (delta < 5400) // 90 * 60
    {
        return "an hour ago";
    }
    if (delta < 86400) // 24 * 60 * 60
    {
        return ts.Hours + " hours ago";
    }
    if (delta < 172800) // 48 * 60 * 60
    {
        return "yesterday";
    }
    if (delta < 2592000) // 30 * 24 * 60 * 60
    {
        return ts.Days + " days ago";
    }
    if (delta < 31104000) // 12 * 30 * 24 * 60 * 60
    {
        int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
        return months <= 1 ? "one month ago" : months + " months ago";
    }
    var years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
    return years <= 1 ? "one year ago" : years + " years ago";
}

public static bool WorkingDay(this DateTime date)
{
    return date.DayOfWeek != DayOfWeek.Saturday && date.DayOfWeek != DayOfWeek.Sunday;
}
public static bool IsWeekend(this DateTime date)
{
    return date.DayOfWeek == DayOfWeek.Saturday || date.DayOfWeek == DayOfWeek.Sunday;
}
public static DateTime NextWorkday(this DateTime date)
{
    var nextDay = date;
    while (!nextDay.WorkingDay())
    {
        nextDay = nextDay.AddDays(1);
    }
    return nextDay;
}

public static DateTime Next(this DateTime current, DayOfWeek dayOfWeek)
{
    int offsetDays = dayOfWeek - current.DayOfWeek;
    if (offsetDays <= 0)
    {
        offsetDays += 7;
    }
    DateTime result = current.AddDays(offsetDays);
    return result;
}