You are definitely not alone. Posed, group photos are, in my opinion, one of the most boring things to photograph...ever, I think the idea of doing them is really a holdover from the earliest days of photography, where perhaps a family could only really afford to have a few photographs taken in their lifetime, and they served a sort of documentary purpose. Nowadays, I'd much rather have individual, interesting photographs of the people I care about, as opposed to a single photograph that includes everyone along the lines of a middle school class photo...but some folks like seeing multiple generations of family in a single shot. Such group shots are my east favorite aspect of wedding photography, too -- I tend to enjoy everything about shooting a wedding, but I can't stand doing the posed group shots.
The only suggestion I have is to think more like a studio or art photographer, and work to create & build the shot with props, interesting composition, lighting, etc. as opposed to a photographer with a more journalistic bent, when doing such photos--I struggle with this because my favorite photos, and I think, the best, most genuine and interesting moments come from capturing human expression & interaction when the subjects aren't aware that you are getting the photo.
It might be worthwhile to scour the web and look at old group/family photos from times past (say, early 1900s), and then attempt to recreate a stylized sort of group photo -- at least it would make things more interesting for you and present a photographic challenge, as I really get what you are saying, if this isn't the kind of photography that interests you, taking posed family shots is worse than having teeth extracted without anesthesia (at least for me).
Alternatively, next time they ask, just give them a coupon to a Sears photo studio.
happy shooting.
