Your opinion: Learning multiple languages at once...?

So next year, as a university senior, I've signed up for German 101, French 101, and Greek 101 simultaneously (all elementary classes). In hindsight it was likely not the best idea ever.

But anyway, what are your thoughts on starting several languages at once? I realize most of you have two or more languages marked as currently learning, but I have a feeling they were staggered; ie. you started one for a few months or years, then started a second language once you had a good grasp on the first. Thoughts, experiences, opinions? Let loose!