Bryson Distributing recently added some new tools, and I had the (amazingly) good sense to order some. The Gauge-O-Knit is a ruler that automatically indicates your gauge - no figuring it out, no multiplying, nada, For those of us who have experienced mathphobia, this is a godsend.
But wait! That's not all! There is also the Calc-O-Knit, for when you want to use yarn of a different gauge than the pattern calls for, or use a different needle size. This gadget tells you exactly what you need to cast on, based on your gauge (determined with the above gadget). You can change a pattern you like to fit you, easily and without errors.
Purls of wisdom: The value of an idea lies in putting it to use.