HTC’s app store for its Vive virtual reality headset expands globally Friday after launching solely in China earlier this year. It’s calledViveport, and HTC says that for the next 48 hours (from 12:00 a.m. PT September 30), it’s marking “several marquee titles” down to a buck a piece. That includes stuff like Mars Odyssey, a normally $8 NASA Lander and Rover infused romp across the red planet, as well as Firebird – La Peri, an otherwise $10 visual fantasy set to French composer Paul Dukas’ ballet.