Dublin -> Barcelona -> Paris -> Vienna -> Prague
Roughly 14 days.
That's a little less than 3 days a city.
My biggest problem with my recent jaunt to Europe was not so much the lack of time, but a lack of will. I spent the first half of the trip (which logged up to Paris on the above list) doing as much as possible. By the 6th or 7th day, I honestly wanted to curl up and not have the responsibility of doing everything I had said I'd do. There was just too much. I'm glad I cut Munich out of my trip - I don't even know where I would have fit it in.
It so happened that a lazy day in Vienna brought on by a previous late night with many drinks and laughs came as a welcome respite. By the time I got to Prague, I just wanted to wander around.
Still, I managed to get out and do most of what I had set out to do. Next time, I won't overload so much.
I'll have more on my trip later. For now I'm going to nurse my jet lag.