Dudle - Dudle is an online scheduling application, which is free and open source.
MINDBODY - Find and book fitness and beauty classes near you.
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Glofox - Powerful Gym and Studio Management Software.
Framadate - Make your polls
WellnessLiving - Wellness Living is a cloud based software features real-time appointment and class scheduling, POS, email and SMS marketing, customer review management, etc.