I’m aware of at least two things going on in Portland for Darwin Day on February 12th.
The Center for Inquiry-Portland will be hanging out between between the Smith and Neuberger buildings on the Portland State University campus from noon to 3:30, passing out cake and talking to people about evolution (last year and 2011 it was at Pioneer Square).
Massimo Pigliucci of the City University of New York will give a Darwin Day talk on the interaction between philosophy and science at 7:00 pm, in SB1 107 (see below for update on location) on the campus of Portland State University. Details on the Meetup page here.
The Dispersal of Darwin 
Update from Glenn Branch of the NCSE:
Just a quick update, since the venue for the event changed, plus a
title and a description of Piglucci’s talk are now available:
I thought that you might like to know that Massimo Pigliucci of the
City University of New York will give a Darwin Day talk on “Evolution,
Neuroscience, Philosophy, and the Meaning of Life” at 7:00 p.m. on
February 12, in the auditorium (room 001) of the Campus Recreation
Center on the campus of Portland State University.
A description of his talk: “At some point or another we all deal with
the big questions in life, questions that concern morality, justice,
friendships, and relationships. Massimo Pigliucci, in his Answers for
Aristotle: How Science and Philosophy Can Lead Us to A More Meaningful
Life draws from the insights of Darwinian evolutionary biology, modern
neuroscience, and timeless philosophical analysis to help us think
about our existence and how to navigate it intelligently. Science
provides us with answers as to where important aspects of human
behavior come from (evolution) and how our brains process them
(neuroscience), while philosophy helps us to reflect on the meaning of
it all.”
For further information, visit:
http://www.pdx.edu/events/darwin-day-speaker-massimo-pigliucci-0