Ugh! As a very involved and very enthusiastic PTO leader, your husbands opinion, and I'm sure others as well, makes me so angry! In our behind the scenes capacity, we know all too well why we have parent groups, and all of the good they do.
Start with the file exchange. There is a great document in there, I think it's the Top 10 reasons to get involved, and it is fantastic!
Have you tried publicizing the accomplishments, and future goals of your group? Our group decides, before our big fundraiser, what we're going to raise the money for, and then we advertise, advertise, advertise, what we're going to buy, and purchase it immediately after the close of the fundraiser. This year it was a mobile iPod Touch lab, which would be utilized by every grade. Kids AND parents were excited about the cool technology we were getting, and we raised more money than we have any other year! At the end of the year, when we make our large donation to the school, they are able to purchase several big ticket items, and we advertise that at the beginning of the next school year in a "welcome back thank you note."
In my experience, surveys haven't gotten a good response. We tried one last year to see how parents felt about events, what they would like to see us do, where they would like to see the money go, etc. and received less than 10 out of over 200.
As silly as it sounds, is the principal your pal? When your group has a good relationship with the principal, he or she can really vouch for all of the work your group does, help promote events, activities and fundraisers, and what the group provides that the school would otherwise have to do without. Whether it's low cost field trips, or assemblies, or classroom supplies, have the principal help you get the word out.
You may not be able to convert everyone, but shining a bright light on all of your groups accomplishments and goals just might turn some heads and get them asking questions, which leads to involvement.
One other thing you may try; in a summer time mailing, we send home a volunteer form. It lists all of the events we have scheduled for the year, along with the dates, and a place for their contact information. Parent check off what interests them, and we contact them before the event, thanking them for signing up in the beginning of the year, asking if they're still available to help, and letting them know what areas need help and what time slots are available. The form is supplemented with an event description list, with a brief summary of the event, and the what the work is like. For example, Book Fair (dates): Volunteers are needed to help set up, assist the students with choosing their purchases, cashiering, and helping to clean up at the close of the event. This way parents know before they sign up what's involved and whether it's something they would enjoy and want to be a part of. You can incorporate the 2 Hour Power Pledge into this, and you have a list of volunteers on hand, well before the event. Most importantly, make sure you contact everyone on the list. There is nothing worse than signing up to help with an event, and never being contacted.
Didn't mean for this to get so wordy, but I hope it helps!