Forest Grove sits in the middle of the Tualatin Valley wine country, the northern arm of the Willamette Valley AVA. Within a fifteen-minute drive you can be at half a dozen serious pinot noir producers -- David Hill, Montinore, Plum Hill, A Blooming Hill, SakeOne (Oregon's only sake brewery). Most are open for tasting on weekends; many take walk-ins.
For non-wine excursions, the Oregon coast is about an hour west through the Coast Range -- Cannon Beach, Manzanita, and the cluster of small fishing villages around Tillamook. Henry Hagg Lake (see Things to Do) is fifteen minutes south. The Columbia River Gorge waterfalls and Mount Hood ski areas are both about 90 minutes east through Portland.
Portland itself is the obvious city day trip -- the museums, the Pearl District, Powell's bookstore -- about 40 minutes by car.