Maybe you could do a parenting survival kit (it sounds like at least some of you are married). If you have some prescription bottles you could put a lable on it with something like "Take one as needed to improve sanity" or "Take one as needed for creativity" and then put some M&M's or skittles or something like that inside. You could also put some little self pampering things in it or some little activities that could be used for the kids to do (Uno, or some other kiddie card games). If you have siblings who travel alot (even if it's just 5-6 hours) maybe a traveling survival kit. Something like that can be as inexpensive or "pricey" as you want to make it. You can also find some fun things to put inside it on the internet, where you just print it off...
I also read in a magazine once, to create a game based on family stories and such. You could do that. You could make a game board with pictures around it showing something from your childhood that has a fun story attached (you can collect memories from family members). Or you could make squares that say something like "Tell your earliest memory", "Tell about your favorite halloween costume", "Tell us your most memorable Christmas". You could do all sorts of fun things with that.
Anyway, I hope maybe that can get you started on brainstorming. It looks like no one else has posted yet. Good luck with it. I don't know what your hobbies and interests are, but these could be done by almost anyone.