Last weekend, we went to a big party at Marieke's school, RUC. I think it was as close to a Homecoming party as we're going to find here. There was no football game, and no alumni come back, but it is definitely the biggest party of the fall. Another major difference is that all the drinking and partying was permitted by the university (even encouraged).
The party began with a huge potluck dinner for each faculty (with plenty of cheap beer). After dinner, they closed and locked all of the university buildings. The party moved outside to where several large tents had been set up (with various bands and Djs playing).
The party continued until sunrise (typical for Denmark), although we were embarassingly Canadian and headed off around 2 or 3 am.