Rocket Jam is the name we give to our promotion company hosted by myself (Phil Platt) and I usually do a warm up spot for the other musicians booked to play the gig, these are not 'open mic nights' but more of a showcase.
For small venues we just take a Studiomaster 300watt traveller PA with 5 channel desk with onboard FX and two small but high quality full range speakers, the set up also includes 2 high quality 'The Box' powered monitor speakers, all in all a great set up for two acoustic guitars and two vocal mics, (we also supply a couple of mics and stands).
Medium venues we have a Peavy/Behringer system with a multicore ect this is about 1K, any bigger we just hire stuff in.
We also bring 2 KAM LED Par Bars which just adds a bit of nice lighting to the events, all very compact but also very high quality as well, the whole shabang can be set up and working in around ten minutes.
The idea of Rocket Jam is to eventually put on three or four of these events every week, we reckon that this will be good as each event will have consistency, in other words musicians and punters alike will have an idea of what to expect, good musicians with a good sound.