Seattle Sounders FC is set to open CenturyLink Field to its full capacity Sunday evening for a home Cascadia Cup clash against the Portland Timbers at 6:30 p.m. Sunday's pre-match ceremonies include a Golden Scarf presentation by former honorees Kasey Keller and Michelle Akers to Washington Youth Soccer in honor of its 50th anniversary, with the pair representing the first half-century of the organization, symbolically passing the torch to the next generation of athletes, including Akili Kasim and Kaylene Pang, both of whom recently represented Washington at the U.S. Youth Soccer National Championships. Prior to Sunday's match, CenturyLink Field is set to play host to the second leg of the Special Olympics Unified Cascadia Challenge Series, with Special Olympics Washington taking on Special Olympics Oregon following the first leg in Portland on July 16.

A TOPSoccer play day will be held on Sunday morning, with over 100 kids and their families expected prior to the match against Portland. TOPSoccer is a program for children four years of age and older with developmental and/or physical disabilities.

The Sounders will also host a soccer equipment and cash donation drive, with volunteers stationed at all entrances throughout the stadium to collect new and gently used soccer gear and equipment, as well as cash donations. Fans can also drop-off donations in Occidental Park from 12:00 - 4:00 p.m. on Sunday, with all donations benefiting another Washington Youth Soccer program, Soccer for Success.

Prior to Sunday's match, the second leg of the Special Olympics Unified Cascadia Challenge Series kicks-off at 1:00 p.m. PT on the Xbox Pitch at CenturyLink Field, featuring athletes from Special Olympics Washington and Oregon representing Sounders FC and the Timbers, respectively. The Special Olympics Washington Sounders edged the Special Olympics Oregon Timbers 6-4 when the teams met in the first leg in Portland on July 16.

On Thursday, fans in Seattle can come check out The RAVE Foundation's Soccer Octagon - a transportable, enclosed field that promotes technical soccer through free play - at Westlake Park during lunchtime from 12:00 - 1:30 p.m. PT.

The work-week concludes on Friday with a pair of appearances, including Cristian Roldan and Tyler Miller participating in a Fred Meyer Bag Off on Friday from 5:00 - 6:00 p.m. PT at the Aurora Avenue location in Shoreline. Meanwhile, Stefan Frei is appearing at McDonald's in Sammamish on Friday from 4:00 - 5:00 p.m. PT, greeting customers, working the drive-through and learning how to make the official French Fries of Sounders FC.

Additional matchday elements on Sunday include a Rave Green DJ Party exclusive for Season Ticket Members at 5:00 p.m. on the Toyota Fan Deck. The RAVE Foundation is hosting street soccer and soccer-themed shuffleboard in Occidental Park from 11:00 a.m. - 4:00 p.m., as well as a charity beer garden in The NINETY pre-match. Fans interested in biking to the match on Sunday can utilize the club's free bike valet, located in the NW corner of CenturyLink Field. Complete information on all matchday activities can be found via the following link: http://sndrs.com/POR821.

Seattle's own Kris Orlowski is set to perform at the March to the Match on Sunday, beginning at 4:00 p.m. PT. The March itself, one of the best traditions in American sports started by the Emerald City Supporters, departs from Occidental Park at 5:30 p.m. PT for CenturyLink Field.

Unbeaten over its past three MLS matches (2-0-1) under Interim Head Coach Brian Schmetzer, Sounders FC now turns its focus to archrival Portland Timbers, beginning with the club's lone home contest against Caleb Porter's side on Sunday, August 21. Kickoff for the full-stadium match is slated for 6:30 p.m. on the Xbox Pitch at CenturyLink Field, with FS1 televising the match nationally.