While perhaps a 5.0 earthquake does not warrant three exclamation marks, a 5.0 earthquake felt while in Tokyo tower does.
We went to Tokyo Tower for Wendy's birthday because they have a birthday deal that involves free cake. We actually live kind of close, so we just walked there from our apartment, waited in line for tickets, purchased them, rode the elevator to main observatory, and observed the view.
Turns out that Tokyo Tower is a hot date spot so there were many couples enjoying the view. This, and the fact that the windows were slightly dirty, made taking pictures difficult. Here's one I took from my phone. It's pretty bad as far as picture go, but you get the idea. I took some with my real camera, but my netbook can't process them (and I forgot the appropriate cable).
Anyway, after enjoying the views from Tokyo Tower we then went to the Tokyo Tower Cafe where they presented us with a free piece of (chocolate) cake. We sat down to eat the cake and suddenly the whole tower started to shake back and forth. The shaking was significant enough to cause the light hanging from the ceiling to noticeably shake back and forth. This went on for perhaps 3 minutes (longer than the earthquake because of the residual motion) and then stopped. No one else seemed that concerned. We then got on the elevator and went to the bottom.