Example of a static class for log4net; adapted from code found at http://stackoverflow.com/a/2853111/41153. Also using optional error-number (GUID) return to hide runtime errors from users.

StaticLogger.cs

using System.Runtime.CompilerServices;
using System.Diagnostics;
using log4net;

// TODO: you must move the below configuration call.
// It must be executed prior to any calls to Logger
// Application_Start or summat
log4net.Config.XmlConfigurator.Configure();

public class CustomError
{
    public string ErrorId;
    public string Message;
}

public static class Logger
{
    private static class UnknownObject { }

    // found @ http://stackoverflow.com/a/2853111/41153
    [MethodImpl(MethodImplOptions.NoInlining)]
    public static ILog GetLogger()
    {
        Type t;
        try { t = new StackFrame(1, false).GetMethod().DeclaringType; }
        catch { t = typeof(UnknownObject); }
        return LogManager.GetLogger(t);
    }

    private static string GetErrorNumber()
    {
        return Guid.NewGuid().ToString();
    }

    public static void Info(object msg)
    {
        GetLogger().Info(msg);
    }

    public static void Error(object msg)
    {
        GetLogger().Error(msg);
    }

    public static CustomError Error(Exception ex)
    {
        var ern = GetErrorNumber();
        GetLogger().Error(string.Format("{0}: {1}", ern, ex));


        string msg;
        // bool that reads from [app|web].config
        if (Settings.VerboseErrors)
        {
            var sb = new StringBuilder();
            sb.AppendLine(ex.ToString());
            sb.AppendLine(string.Empty);
            sb.AppendLine(
                "(This message is displayed because VerboseErrors is set to true. Please set to false to only display ErrorIDs)");

            msg = sb.ToString().Replace(Environment.NewLine, "<br />");
        }
        else
        {
            msg = string.Format("An error has occured: Please contact support with case-number {1}", ern);
        }

        return new CustomError { ErrorId = ern, Message = msg };
    }
}