Geib actually entered the 7:30 p.m. contest tied-for-10th in team history with 66 points and added two more with the game's first goal at 12:33. His third goal this season was assisted by Aubert and junior Alen Hataric.
The Foresters outshot the Red Men 16-8 in the opening period and led 1-0 when it ended. They also had a 6-4 advantage in shots during the second half but surrendered goals in the 62nd and 78th minutes.
Aubert converted a penalty kick opportunity with 2:57 on the clock to tie the score and eventually force overtime. The goal was his team-high eighth of the season and he joined Geib with 68 points in his career. He has scored or assisted on 13 of the team's 16 goals this season.
Carthage finally netted the game-winner two minutes and 17 seconds into the second extra period.
Lake Forest attempted 22 shots and the Red Men 14 but both teams finished the contest with 10 shots on goal. Forester junior Jan Roessler matched his career-high with seven saves.
The loss dropped the Foresters' record on the season to 4-6-1 while Carthage improved to 6-5-0.
It was the final non-conference game of the regular season for Lake Forest, which will resume Midwest Conference play at Ripon College Saturday afternoon at 3:30.