Celcat Timetabler - Celcat Timetabler is the complete, state of the art solution for optimising resource utilisation, timetable publication, ad-hoc room booking, attendance tracking, pay claim management...
Skedda - Offices, co-working spaces, universities, sports venues, studios & churches are just some of the places that manage the use of their desks, rooms, courts, studios, halls and all other 'spaces' with Skedda
Booked Scheduler - Booked (formerly phpScheduleIt) is a simple but powerful reserve-anything scheduler.
Teem - Cloud-based meeting room booking system
Classroombookings - Open source hassle-free room booking system for schools.
AskCody - Meeting management system for Outlook & Office 365.