WintelGuy.com

Tools
Ethernet MAC Address Lookup / Fibre Channel WWN, WWPN, WWNN Lookup / Vendor Lookup
Gigabyte (GB) to Gibibyte (GiB) Converter - provides quick conversion between gibibyte (230 bytes), mebibyte (220 bytes), gigabyte (109 bytes), and megabyte (106 bytes).
Binary to Decimal to Hexadecimal Converter
IP Locator - finds the geographical location of an IP address or host.
WHOIS Lockup for IPs and many popular top-level domains.
EMail Tracer - analyzes email headers and presents basic information about an email massage in an easy to read table form.
IP Subnet Calculator
Password Generator - random password generator. Passwords can be from 7 to 16 characters long with a random distribution of lower-case characters, upper-case characters, digits, and non-alphanumeric characters.
What is my IP address? - displays connected computer's IP address, host name and other details obtained from user agent string.
RAID calculator computes array characteristics based on the the RAID level, the number of disks, and the disk capacity.
ROT13 Coder - ROT13 and ROT47 (rotating substitution ciphers) encoder / decoder.

General
IEEE Registration Authority - OUI Public Listings
Guidelines for Use of the 24-bit Organizationally Unique Identifiers (OUI) (IEEE)
The Unicode Character Code Charts
ISO lists of country names and code elements
IANA's Root Zone Database
TLD and CLTLD whois servers list
Tethering - how to tether (interconnect) a mobile phone and a laptop, PC, or tablet in order to share phone's Internet connection.

Network
Ether Types/Vendor Addresses/Multicast Addresses (IANA)
Wireshark (formerly Ethereal), a software network traffic analyser
IP Subnet Calculator
Subnet Mask Table
How to add MAC address to wireless router
IPv6 Addressing Cheat Sheet
Data Transfer Rate Converter

SAN / Storage
Guidelines for Fibre Channel Use of the Company_id (IEEE)
How to clear SCSI reservation on a LUN
Clariion NaviSecCLI Cheat Sheet
RAID Capacity Calculator computes array capacity and other characteristics based on the the RAID level, the number of disks, and the disk capacity.
RAID Performance Calculator
RAID Reliability Calculator computes storage system reliability using well-known MTTDL methodology. Supported RAID levels are RAID 5, RAID 6 / RAID-DP, RAID 10 (1+0).
Hard Disk Performance Basics
Simple disk throughput tests using dd utility

UNIX/Linux
I've just installed CentOS 6! Now what? - CentOS Initial Set up and Configuration
File Mode Creation Mask / umask Calculator
Unix Permissions / chmod Calculator

Web
Full Web Building Tutorials - All Free - W3Schools.com
JavaScript Event KeyCode Test Page

Other Stuff
Despair, Inc.
Dilbert.com
GradeCalc.info - Weighted Grade / GPA Calculators and Final Grade Calculators specially adapted for a number of Canadian and US universities and colleges.
TotalCalc.info - Free unit converters and calculators from many different knowledge fields and areas.