I'm a bit late with this one, but last night there was a strong earthquake.
USGS data from their earthquake site:
And the 'graph from OVSICORI, the Volcano and Seismic Center at the National University (UNA)
The center of the quake was about 20 miles from here, and if you know anything about Costa Rica, about 2 miles west of the caldera of Poas Volcano.
My experience of this one was: a low shake for a moment, which grew to a large shake and then strong side to side movement for about 3-4 seconds... just long enough to make you wonder if it was gonna stop any time soon. Certainly the most ... impressive ... quake I've experienced in the 19 months I've been in Costa Rica.
All in all, pretty dang cool. :)