We ask folks to bring whatever snacks they may want, adult beverages for themselves, a coffee cup maybe. Now of course many bring extra for all so it's not necessary really.
Food wise from Friday dinner to Sunday breakfast it's supplied. I know folks like to contribute, desserts are welcome. I've found out it's easier for me to supply the main dishes and way too hard to keep track of who's bringing what... I end up with too many eggs and not enough of other things... if someone has to back out I have to figure what it was they were bringing and compensate.
Much easier if I have control and as Ed said a small food donation is accepted but not mandatory, food money is carried over from each event, it has always worked out. Mostly us locals want to host and those traveling just get here, bring shooting irons, have a good time and travel safe.
