Turrialba volcano in Costa Rica.
Turrialba, one of Costa Rica's active volcanoes, is apparently showing signs of life according to a brief report by Teletica 7 (in spanish). There is increased seismic activity and elevated gas emissions at the volcano that last erupted in 2007* and 1866 prior to that. The fumarolic activity at the summit crater is not a new occurrence, however the report implies that it has gotten more intense as the volcano has experienced increasing seismicity since early May. The Volcanism Blog does have an excellent summary of the rumblings at Turrialba since earlier in 2009. The volcano is the eastern-most active volcano in Costa Rica and is located with a national park.
The eruption in 1866 was fairly significant, ranking as a VEI 3 and producing 10,000,000 m3 of erupted tephra, lahars and pyroclastic flows over a 5 month span, as the culminated of frequent eruptions during the mid 1800s. Prior to this, the volcano has had a number of reported eruptions during the last few thousand years, including a VEI 4 around 40 A.D. (known by carbon dating).
* oddly, the Smithsonian GVP had no record of the 2007 eruption of Turrialba, not even in the weekly or monthly reports archived on the site. Wikipedia also makes no mention of this 2007 eruption, but does mention increased activity in 2001. Other reports seem to suggest that the event in 2007 wasn't an eruption per se, but rather very intense steam plumes from the summit craters. In any case, there might be some confusion out there about what constitutes an "eruption". However, one thing is sure: since 2007, the volcano has been closely watched.