The FEL gain can be significantly increased using a distributed optical klystron (DOK) FEL with multiple wigglers and bunchers. The enhanced FEL gain of DOK FELs opens the door for storage ring based FEL oscillators to operate in the VUV region toward 150 nm and beyond. This presentation reports the first experimental results from the world's first distributed optical klystron FEL, the DOK-1 FEL, at Duke University. The DOK-1 FEL is a hybrid system, comprised of four wigglers: two horizontal and two helical. With the DOK-1 FEL, we have obtained the highest FEL gain among all storage ring based FELs at $47.8$\%($\pm2.7$\%) per pass at 450 nm. We have also realized controlled polarization switches of the FEL beam by a non-optical means through the manipulation of a buncher magnet.  DOK FELs are promising light sources capable of rapid polarization switch in UV and VUV. Furthermore, DOK FELs can be used as a multi-color light source with multiple lasing lines and harmonic generation.