Before taking the ice each period, members of the men's hockey team reach up to tap a sign that says "Our House" as they move from the locker room into Alfond Arena. It's a tradition that began before this year's six senior players arrived at Colby. Despite the ritual, though, the team's last regular-season game in "Our House" was a disappointing 2-1 loss to Amherst.     Even with the loss, Colby's regular season was strong enough to earn the team a third seed in the ECAC Division III tournament. When tourney pairings were announced the men received another chance to make the last game at "Our House" a win when they drew home ice for the quarterfinal game on February 27 against Connecticut College. When that contest was over the players gathered at center ice and raised their sticks to celebrate a 5-0 win over the Conn College Camels and the first shutout of the season for goaltender and assistant captain Jason Cherella '99.     The White Mules' (13-9-4) season ended a week later with a 3-1 loss in the ECAC semifinals. But Colby players were able to heed Coach Jim Tortorella's directive to "hang your Colby jersey up with pride"--no one more so perhaps than Captain Rob Koh '99. A two-time All American and likely to earn the hat trick when this year's All Americans are announced, Koh is the only Division III player from the East going to a team of American college all-stars who will compete against Canadian college all-stars in two post-season games this spring.