This may be off topic, but I use the multiple calendar view in Outlook all the time (okay, once in a while). It'd be great to somehow see the calendars overlaid...with some transparency on the foreground calendar(s).
Not sure how you would make it work...but for example, let's say I were at Gnomedex and subscribed to the schedule. I'd want to see a transparent version of the Gnomedex schedule on top of my personal schedule (the base)...instead of side-by-side.
Probably not an important feature, but it would have a lot of coolness factor.