Stereoscopic Player allows you to play numerous types of 3D content such as:
Field-Sequential 3D DVDs (an interlaced format that is becoming obsolete)
Sensio 3D DVDs (side-by-side compressed 3D)
Side-by-Side/Over-Under 3D files
Internet streaming 3D content (i.e., April's Masters tournament)
and, hopefully, Blu-Ray 3D content
Try googling field-sequential 3D or Buy Sensio 3D DVDs to find some content.