I went, I queued for 30 minutes to get into the botanical gardens - only to be disappointed. Too dark to see anything and they wouldn't let you wander around.
I walked up to Plaza Mayor after that after wandering around a bit down in Castellana and, of course, stopping for some tapas in a terrace.
Plaza Mayor was crazy, they were giving away free balloons and people were almost fighting for them at times. unbelieveable how rational people can act when there is free stuff, especially when the free stuff is pretty useless.
Anyway, the atmosphere was great in the streets, and it was a nice evening.
The only thing that spoilt the night a little was when I was going home and saw a group of yobs on the platform in Gran Via metro station trying to intimidate a few people. they were just being loud, spitting, staring at people etc. (I guess they *thought* that they were Latin Kings)