These are the workhorse lighting instruments of the the industry. Lekos are used to light just about everything on stage. They are able to be focused on specific places and have shutters that cut off excess light. They have interchangeable lenses to make the beam wider or narrower. The industry standard is the Source Four, made by ETC. The Source Four was released in 1992 and quickly became the must-have light for theatres everywhere. They unique reflector provides the punch of a 1000 W lamp with a 575 W bulb, which keeps the unit cooler and preserves your templates and gels.
PAR is short for parabolic reflector. These lights often have gels, which are pieces of colored material, and they are used to add some punch and color to a show. ETC also makes a Source Four par. These are more compact and efficient and are used much more frequently that the older PAR 64 units. They are also very common and easy to find and get serviced.
Strip lights, or cyc lights are used to light up backdrops with different colors. There are many different kinds of strip lights, and each has its advantages. Ministrips are smaller and can be used in smaller spaces. Altman Lighting makes a much larger Sky Cyc, designed to create an even wash over the backdrop. Sky Cycs require more energy and will use more gel to cover them. Ministrips are more compact and, because the lamp face is small, they will not need a lot of gel.
Moving lights are increasingly common in theatres, clubs and schools. These are lights that are controlled from a lighting board and can change color, beam size and template shape with the turn of a dial. These lights often require specialized control boards, so make sure you have one before you invest in the lights. ETC makes the Revolution for Source Four, which is essentially a Source Four unit that has been equipped for movement. Apollo Lighting makes the Right Arm, which is a controllable yoke that will allow you to pan and tilt conventional lighting. This may be a good option if you want to use moving lights and you have extra lekos at your theatre.