Sounds like an interesting idea!
Right now, I have time at about everytime - but that will change in April when the lectures start again. I do agree that Tuesday is impossible, the best on the other hand would be the weekends, as I am also GMT+1, I guess the times Mortem mentionend are fine. During the semester, it is going to depend on whether there is a lecture late that day or early the next day, can't say much about that yet.
Umm, Mortem, I just remembered... concerning Wednesdays... don't they shut down the servers on that very day for the "weekly maintenance"?