The Calhoun College dining hall was packed last night with trays of refreshments, aerial photographs of the Yale campus and a high-tech sound system. For the first forum on the largest proposed expansion to Yale College in a half century, administrators expected a large turnout.

Instead, more administrators were on hand for the forum than undergraduates.

Discussion of Yale’s most important decision in decades apparently lost out to midterms, the rainy evening and the first game of the World Series, much to the chagrin of organizers.

At 9 p.m., with a dozen Yale officials on hand and a Yale police officer lingering, ostensibly for crowd control, a lone undergraduate sat in the dining hall for the forum — the first of five to be held over the next two weeks in an effort to include student input in administrators’ deliberations over whether to build two new colleges.

A few more students trickled in by the time Calhoun Master Jonathan Holloway opened the proceedings at 9:10 p.m. The crowd was so small that administrators forwent microphones.

Most of the attendees were student or faculty members of the two committees charged with assessing the new colleges’ impact on academics and student life at Yale.

The committees are expected to release their recommendations regarding the colleges in January, and the Yale Corporation is scheduled to vote in February on whether to build the new colleges, the cost of which has been projected at close to $600 million.

The University announced the forums in an e-mail to all undergraduates on Monday afternoon. The entire Calhoun dining hall was cleared for the event, with two microphones and a sound system set up. Among the refreshments available were eight platters of brownies and cookies, as well as enough Coke, Diet Coke and water to refresh dozens of students.

Most of that food went uneaten.

“It’s a little disappointing,” said William Sledge, a former Calhoun master and the chairman of the student life committee, after the forum. “We were hoping to get a more lively conversation. We’re interested in what the students think about this, because a lot of it hasn’t been decided.”

The one student who was in attendance at 9 p.m., Brendan Woo ’08, said he was motivated to attend out of “curiosity.”

“Turnout at things like this is usually unpredictable, I guess,” he said.

The small crowd notwithstanding, the few students in attendance had more than enough questions about the colleges to sustain discussion for more than an hour, and committee members huddled around the aerial maps and brainstormed ideas with students long after the event had officially ended.

The forums are intended to draw that type of student input into the process, said Emily Weissler ’09, a member of the student life committee and one of the four student committee members in attendance at the forum.

“We’ve thought long and hard, but we also realize that as a group of people we don’t represent all the diverse opinions at Yale,” Weissler said to the half-dozen students on hand who were not members of the committees. “That’s why we’re turning to you.”

The remaining forums are scheduled for 9 p.m. tonight in the Pierson College dining hall; Oct. 30, in the Saybrook College common room; Nov. 1 in the Morse dining hall; and Nov. 5 in the Silliman master’s house.