One of my favourite sayings is that it doesn't matter how much time I work on Jomres, it never fails to amaze me how creative people can be when it comes to using it to suit their own requirements.
Historically I've always shied away from recommending using Jomres as an appointment or slot booking application because, well, it was never really written for that use. Lately, however, I've seen several sites using Jomres for just that purpose and I thought that I would explain to people why, although it is strictly speaking a by-the-day booking application, Jomres can be easily adapted for time-based bookings.
First, let's revisit the Jomres booking process for those people who might not be familiar with the system.
In Jomres there are properties (e.g. a hotel). A property (unless it's an SRP) can have multiple rooms of multiple types. For each room type, you have a tariff. When a guest makes a booking for a room they're making a booking for a combination of room at a certain tariff.
How are the appointment booking people using the system?
Let's take an example I've seen recently, of a golf course booking site. The main adjustment they've made is to the language file, changing "rooms" to "slots", "room types" to "slot types" etc. Once they've done this it's very easy to shift your mental focus away from just property management, to time based bookings. Changing wording for an individual property is extremely easy, and Jomres offers several different ways to do this, you can see more at Translating Jomres.
What they are doing is they are treating the rooms as slots, e.g. a 10-11am slot, 11am-12pm slot etc. Next, they're associating these slots with a slot type (e.g. a room type becomes a 10am-11am slot type). After this, they can control which days of the week and year the slot is available by creating tariffs associated with that slot type using the Advanced Tariff Editing mode. They have also switched off the departure date input in the booking form so that the "booking" only happens on a given day.
So, as you can see that whilst it's built as a by-the-day booking system, there's really no reason why you can't use it for making appointments or for hiring out equipment, it's really just a case of using your imagination and running with it.
Another way to do it
Another way to allow booking of resources by timeslot is to use the Jintour plugin and create resources that have timeslots in the title, e.g. Driving range 10am - 11am. The advantage of this method is that you can still use the room booking functionality for, say, a hotel, and offer out slots in the hotel's driving range.
Usually in Jomres there's more than one way to skin a cat.