I like charby's response.
Ours went off falsely so much that I decided I wasn't going to leave until I smelled something burning. One night I was working late, the alarm went off and I smelled something burning. I made it down to the second floor (using the stairs, of course) where some guys were working in the bank. It was hard to breath, but they had been cutting a bunch of hard stuff and I figured that's what I smelled. A fire truck pulled up and everyone just thought it was a false alarm, so the truck was leaving. A worker came running down the stairs, yelling (in a Mexican accent) "dude, the *expletive deleted*it's on fire!" I flagged down the firemen before they pulled away. A few more trucks showed up and they ran some hoses up and put out a fire. I got a little free press out of it. The whole building (including our offices) had a nasty burnt smell for a couple of weeks after. After realizing how hard it would be to evacuate a full building with toxic smoke in the stairs, I now pay a little more attention to the alarms. Next time, I'll go across the street and have a beer or two while someone else figures out whether there's really a fire or not.
