It's San Jose's Christmas season fiesta. I think there are several activities, but what I remember from 2005 is that at night bags of confetti are given out to people on Ave. Central and people take delight in throwing it onto everyone else. I didn't know this then, and got doused several times while trying to get to McDonald's for dinner

Oh yeah, and some drunken middle-aged Tica goverment worker (no, not doable at all, and she said "me no prostitute"

) dragged me into a soda for more drinks.

I don't touch the hard stuff so I said goodbye and got out there quickly.
And I also remember fireworks, they went off as me and my then-favorita finished up a session in the Del Rey.
edit, ID mentioned the parade, that's the main activity.