Gran Fondo! The "big day" is catching on!
Gran Fondos are taking the bike scene by storm! They started in Italy but they've spread over here in the USA bigtime.
Levi Leipheimer is hosting one that I posted about here already.
Then there's the Cino Heroica: http://www.facebook.com/group.php?gid=112710501068. It's a two-day ride into the mountains in Montana, mostly on dirt roads and mostly with riders on vintage steel bikes. (Organized by Henry Roberts, an appreciator of OYB bags who rode l'Eroica in 2009, using said bags. Report elsewhere at OYB.)
Maybe l'Eroica is the grandaddy. It seems that Gran Fondos go for Big but they also go for Style. L'Eroica with its limit on only bikes pre-1983 is famous for its style. Thousands respond and revel in the heritage AND the exertion. (I've posted about it here as well.)
I recall hearing about famous "supertours" in Austria and elsewhere in Europe in the late 80's that Masters age riders loved to eat up, so who knows where they came from. Big Days have always been a big part of cycling. Maybe for awhile the world kinda overlooked them. Maybe after the "fun" of 24-hr mt-bike events spread then other cyclists wanted to do big days, too.
I don't know if there's a hard'n'fast rule, but basically it seems like they're "really big days" on pavement or mixed-surfaces. They're sometimes a lot like races, but they tend to be too big for that. They sometimes seem to have THOUSANDS of riders on them. Everyone tries to do their best. They often have timing chips. Maybe they're like the World Loppets of XC skiing: like the Vasaloppet of Sweden, an ancient 90km classic ski event that thousands do each year like a holy pilgrimage.