Consider, for a moment, those superbright LED keyring torches that are currently available.
Imagine, if you will, a somehow cheap enough radio means which, like bluetooth, allows transmission of arbitration data, without the full expense of bluetooth. So, yes, bluetooth, only cheap.
It would be
quite synergistic and indicative of a bigger-than-all-of-us zeitgeist to facilitate people in a party mood to be able to illuminate their torches in such a manner that your immediate neighbouring group of similarly endowed comrades also form part of a pretty pattern.
The temporal arbitration imbued by this protocol allows such effects as: 'strobe' (where all the lights flash at something like 11Hz and in exact sync); 'whirlwind' (where the lights flash but in a pass-to-the-left neighbour motion); 'brownian noise' (where there is a constant amount of light on, but randomly pulsed from a different source at any given time). Other effects no doubt are possible.
Obviously, this works best the more people involved - but if there's only one or two of you, that's not really much of a party, is it.