With its “Celebration of Cycling” moniker again adjusted, the Sea Otter Classic begins Thursday with its usual varied collection cyclists pedaling throughout Laguna Seca Recreation Area in a constant four-day frenzy.

Newcomers to world titlists, grandparents to Olympic gold medalists, riders in more than 200 categories will compete in the 21st gathering’s edition, cycling’s collective impersonation of a Grateful Dead concert. Hundreds of Monterey Peninsula athletes will participate.

“I look at Sea Otter now basically in three ways, said Frank Yohannan, the event co-founder and CEO in 1991. “There’s the competition, the festival (vendors, instruction, exhibitions) and the community component. Sometimes, I forget … no, I don’t forget. But sometimes I just have to realize how important it is to the Monterey Peninsula.”

Like other key annual sporting events — the AT&T Pebble Beach National Pro-Am to the Moto GP to the Salinas Rodeo — the Sea Otter Classic attracts several thousand participants. Camping on the hillsides of the recreation area — the hub of events — shares billing with motel and hotel accommodations.

Since its debut with about 300 athletes, the focus of the Sea Otter Classic has changed more than once. Both men’s and women’s road racing and mountain biking have been the dominant components. But as the prestige and prize money of races fluctuated, so too has the Sea Otter Classic presentation.

“We’re in communication with the teams all the time,” said Yohannan. “We take a look each year and adjust. But pretty much what cyclists, pros and weekend athletes, like to do, is ride their bikes.”

As per tradition, mountain biking, road cycling and gravity event disciplines, will all return. Hand cycling divisions are new this year as is Speed Style. Organizers describe its as “a combination of a head-to-head race and a freestyle jump contest.”

Single-speed purists, tandem mountain bikers, and road and mountain bike gran fondos (organized fun rides) will also have their place in the gathering of an estimated 8,500 riders and 50,000 spectators. The non-competitive festival component will include more than 300 vendors.

Nine categories of criteriums (a timed race of repeated short loops) on Laguna Seca Raceway will launch the road racing schedule at 8 a.m. Thursday. The pro men’s division will conclude opening day at 4:05 p.m.

For pro men and women, the criterium will also mark the first day of a return of a four-day stage race. In addition to the criterium, combined results from the road race (Friday), time trial (Saturday) and circuit race (Sunday) will determine overall men’s and women’s titlists.

Paul Mach, a graduate student at UC Davis, won the Sea Otter pro road race and circuit races last year, and with Bissell pro squad dominating road divisions. Mach and several teammates, including twin brothers Ben and Andy Jacques-Maynes of Watsonville will return.

Ben Jacques-Maynes has won many Northern California races during his decade-long career and has competed in every edition of the Tour of California. Andy Jacques-Maynes was a Sea Otter race winner in 2009.

The smaller women’s field’s leading entrants include Meredith Miller (TIBCO) of Ft. Collins, Colo., the 2009 national road titlist. Teammate Alison Powers of Pinecliffe, Colo., was scheduled to defend her 2010 circuit race title. But Powers suffered several fractures during a crash at the recent Redlands Bicycle Classic.

Peggy Legrand of Monterey is also entered in the women’s stage race and Rebecca Rusch (Specialized) of Ketchum, Idaho, the three-time world 24-hour solo mountain bike world title, will also compete.

Pro mountain bike racing will also be adjusted this year. Dual slalom qualifying will open competition at 1 p.m. Thursday and it will continue through Sunday’s downhill finals at 2 p.m.

The men’s and women’s pro cross country events usually provide the traditional festival’s anticipated finale. But via riders’ requests for larger exposure to race crowds and sponsors, the pro cross country finals will be held Saturday. Women will race at 11:45 a.m., with the men’s race scheduled at 2 p.m.

Georgia Gould (LUNA-Chix) of Ft. Collins, Colo., the two-time defending women’s titlist, and Todd Wells (Specialized) of Durango, Colo., the three-time national cross country titlist who placed third last year at Sea Otter, are entered in deep cross country fields. Defending men’s titlist Burry Sander of South Africa and Geoff Kabush of British Columbia are not entered, both likely preparing for the World Cup season next week in Pietermaritzburg, South Africa.

Facts & Figures: Sea Otter Classic 2011

What: 21st annual Sea Otter Classic, April 14-17.
Where: Laguna Seca Recreation Area, Monterey.
Admission: Festival is free to children ages 12 and under and to all registered competitive and recreation athletes. General public is $10 for a one-day pass, $30 for a four-day pass. Active or retired military can receive two-for-one tickets with military identification.
Parking: Free, with priority areas to carpoolers and hybrid, electric and other “green” vehicles. Valet parking for cyclists.
Festival Hours: Thursday-Saturday, 9 a.m.-5 p.m.; Sunday, 9 a.m.-4 p.m.
Information/Registration: www.seaotterclassic.com, phone: (800) 218-8411 or (831) 373-2331.