Answer by taking a quote from the following article:

Boyz II Men is an American R&B vocal group from Philadelphia, Pennsylvania, best known for emotional ballads and a cappella harmonies. They are currently a trio composed of baritone Nathan Morris alongside tenors Wanya Morris and Shawn Stockman. During the 1990s, Boyz II Men found fame on Motown Records as a quartet including bass Michael McCary, who left the group in 2003 due to health issues. During the 1990s, Boyz II Men gained international success.

Boyz II Men headlined a "Love Cruise" in honor of their 20th anniversary and in observance of Valentine's Day. The cruise took place February 11-14, 2011, and traveled from Miami, Florida, to Nassau, Bahamas. Cruise passengers received a Boyz II Men welcome cocktail party, a concert performance by Boyz II Men, an additional fan appreciation concert by Boyz II Men, a photo session with Boyz II Men (in small groups), a formal prom night, a poker tournament, a deck party with Boyz II Men and a guest DJ, a singles mixer, a gift bag, and onboard drawings for other Boyz II Men events. Couples were able to renew their wedding vows in a special ceremony with Boyz II Men. Twenty, named in recognition of Boyz II Men's twenty years in the music business, is a double CD album with thirteen original songs and eight rerecorded Boyz II Men classics. It was released on October 25, 2011. Twenty is the group's fourth release through MSM Music Group. It was released in Japan 13 days before its official US release date with the help of Avex Group, the biggest Japanese independent record label. Originally, Boyz II Men announced a reunion with original member Michael McCary for the Twenty album. On September 6, 2009, at a concert in Virginia Beach, Virginia, Stockman announced that their upcoming 20th anniversary album "include all 4 members", sparking a tremendous applause. But soon after that announcement, McCary declined and did not join the project. Boyz II Men contributed a cover of Japanese rock band L'Arc~en~Ciel's song "Snow Drop" to their 2012 tribute album.

What else did they do?
an additional fan appreciation concert by Boyz II Men, a photo session with Boyz II Men (in small groups), a formal prom night, a poker tournament,