The powerful interactive Race Calendar launched in March by Slowtwitch.com now packs a more formidable punch. Last week a "rating" feature was added, and many of Slowtwitch's 147,000 cookied monthly visitors have rated races already.

Races can be rated across such categories as course density, fairness and marshals, post-race food, and how promptly the race starts and generates its results.

As of this writing, a whopping 64 Slowtwitch readers took time to rate the Ford Ironman Arizona, giving it moderate marks for "Competitor Density on Course," and "Pre and Post Race Food," while giving it 5 stars (the highest rating possible) on Aid Stations, prompt Start Time, and on the Posting of Results.

The highest rated race among the nearly 1500 North American events on the Slowtwitch Calendar is the Timberman 70.3 Triathlon, with an average of 4.67 stars out of 5. Georgia's Tugaloo Triathlon rates second, and the Suburu Ironman Canada is third. Click to see the entire top-10 list.

If you click on the pages above and find that Ironman Arizona's ratings differ from those reported herein, or that Timberman is not the top rated North American event, it's a function of readers' changing preferences. That's the nature of interactivity.