I've used one of these to power a concert or event. @ 275kva it will provide over 1,000 amps of power. However if you have a big PA (sound system) and or a light show you are going to need the extra size as the fluctuating demand will confuse smaller units and they will shut them selves down. They come on the back of a truck and get hiab'd into position.
A road tow unit unit like this can produce 100kva or 400+ amps which could power up to 30 bouncy castles or a small event. Normally they come with a inbuilt tank of diesel, which last for 12 hours or so.
Small 3 phase road tow Generator. 16kva Generator. Don't be two afraid of 3 phase as it's you can think of it as 3 separate single phase supplies. So for example each "phase" could run a different marquee. The only concern is that each "phase" has a suitable separation from each other. You also need to make sure that if you are nearing the capacity of the generator you balance each phase. Or you can accept that one phase is 1/3 of the power of the generator.
Used for Motor homes and caravans along with any body needing a "clean" power supply in remote locations. The Honda EX650 Generator was the quietest so far by Honda and very reliable. Powered with a 76 cc 1.6 HP Honda sidestroke engine, the Honda EX650 generator delivers performance and reliability like none before.
Compact 2.4kva petrol Generator with a Honda engine. Can produce 110v for building site work or 240v for normal applications. Don't expect the electricity to be as "smooth" as an inverter or one of the larger generators.