Since I am always the one who offers my home as the host home, I have a few tips for preparing so that everything is ready for Cooking Day.
I should also say here that it's not that anyone else doesn't want to host, this just works out well for our group and our circumstances. I have the youngest child (so far) and it makes it easier for naps and such for me to cook in my own home. I have a kitchen with, perhaps, not alot of counter space, but it does have alot of open space and room for tables (we use three!) so we can spread out while cooking.
One thing I always try to do is be available the day before cooking day so the grocery shopper can come and unload the groceries into my fridge. This works well so that there's only one unloading of food and in the morning on cooking day, everything is ready to go. It also gives us a chance to double check against the grocery list and make sure we have everything.
The shopper and I will usually go over the recipes one more time to determine what, if anything, can be done ahead of time to make cooking day go smoother. We can split up the items at this point. For example, in March I precooked the noodles for the Mac & Cheese and Jodi took home the peanuts to chop up for the Creamy Peanut Chicken.
Either the night before, or the morning of cooking day, I print a copy of each recipe and put it in a plastic page protector. I also type up labels that have the name, date, and reheating instructions for each meal and print these out as well.
The plastic page protectors are stored in our pantry bin so now is a good time to bring this out as well (it lives in my guest bedroom the rest of the month!)
It's nice to have everything in one place when we start cooking so I bring up from the basement my extra large Tupperware bowls that I don't use everyday and get out other items from my cabinets that I'm pretty sure we'll use.
I don't mind at all when these ladies go into my cabinets or drawers (and if you're hosting a cooking session, you should expect this!) but it's just easier to have them available on counters and tables.
My kitchen doesn't have a huge amount of counter space so I get out a card table for an extra work surface. This, in addition to my two kitchen tables (one acts like an island for me) is generally enough room for 4 of us to work.
I also make sure my dish draining rack is empty, there is a new clean bag in my garbage can, that there is dish soap in the dispenser and that there are plenty of clean towels around for drying hands and dishes (we go through at least 6 every cooking day).
This is all in addition to making sure my house is picked up as I would before any company comes over and making sure the kids have a safe place to play and toys to occupy themselves with.
It may seem like alot of work but it's not that bad. It was worse when I had people asking for items and I had to run around to get them instead of working on making a meal. I would much rather take some time the night before to ensure everything runs well on cooking day.
See also: Group Freezer Cooking - Planning; Group Freezer Cooking - Cooking Day